Ito, ito ang ultimate gauge ng kaastigan ng school nyo!

[paparagon]

ok, sa ngayon hirap na hirap talaga ako sa school work ko kaya mag-popost ako ng problems ko na di ko makuha at pakita nya na astig kayo (at ang school na ni-re-represent nyo) through answering them. diba ayos! may gauge na kayo sa katalinuhan natulungan nyo pa ako sa Homework. Tandaan nasa 2nd Year Canadian College level to. Marami dito engineering (elec at comp), engineering at math related:

Ito una galing sa physics ko! [*** nasa brackets na to points lang yun kinuha ko to sa assignment sheet ko]

1. The year is 2146, and Martian Mining & Engineering is building an ore processing plant on the rim of Erebus Crater. You are off on an extended coffee break at the ice cream shop on the far side of the crater, 300 m away, and you can see someone using a hammer back at the plant.
The atmosphere of Mars is essentially pure carbon dioxide (CO2), and the molar masses of carbon and oxygen are 12 g/mol and 16 g/mol, respectively. The ratio of specific heats for CO2 is 1.30. The air pressure is 6.78 mb (millibars), and the air temperature is a balmy (for Mars) –27°C. 1 bar = 106 Pa.
a. It seems odd, but you notice that the hammer hits silently, and the “bang” occurs at the top of every swing. What is the period (number of seconds between hits) of the hammer? If necessary, assume that the period has its longest possible value for this to happen, and the hammer reaches the top of its swing half way between hits.
[4]
b. What mechanical impedance does the Martian atmosphere present to the sound waves propagating through it?
[3]
2. A transmission tower is anchored to the rim of the crater by 1.20-cm diameter steel cables stretched to a tension of 12,000 N. A technician is using a signal generator to test mechanical properties of one of the cables by sending a 125-Hz transverse wave of amplitude 0.300 mm along the cable.
[3]
a. What is the speed of transverse waves on the cable? The density of steel is 7800 kg/m–3. [HINT: It may help to find the mass of a 1-m length of the cable.]
b. What mechanical impedance does the cable offer to these waves?
[2]
[3]
c. What time-averaged power is carried by these waves?
[3]
d. What is the maximum angle that the transverse waves make with the undisplaced cable (i.e., with the equilibrium line for the waves)?
e. The signal generator also produces 125-Hz sound waves in the cable. What is the wavelength of these sound waves? Young’s modulus for steel is 20 x 1010 Pa.

ito sa electrical engg at math

Laplace transform daw:

use laplace transform to find y(t)

y'' + y' + y = 0 and y(0) = 2 and y0(0) = −3

[atenean_blooded]

Kaastigan ng school?

www.partyschools.com

[DarkMatrix01]

HHhhhhhmmmm....

tough one....

I wish i can help you but my field is far from what you are doing...

Lets see who can help you with this...

I wonder if someone will try to answer those problems...

[paparagon]

lol wala bang sasagot- alam ko na pano natuklasan ko lang kanina. pero para na to sa inyo na-nagyayabangan ng mga eskuela- baka puro salita lang- mga salita na dinaman ni-re-reflect ang level nyo ng education. kaya magsagutan na kayo!

[sue_mo!]

paparagon,

when in doubt, always choose letter A. for astig.

[flsfnoeraekadad]

ok, sa ngayon hirap na hirap talaga ako sa school work ko kaya mag-popost ako ng problems ko na di ko makuha at pakita nya na astig kayo (at ang school na ni-re-represent nyo) through answering them. diba ayos! may gauge na kayo sa katalinuhan natulungan nyo pa ako sa Homework. Tandaan nasa 2nd Year Canadian College level to. Marami dito engineering (elec at comp), engineering at math related:

Ito una galing sa physics ko! [*** nasa brackets na to points lang yun kinuha ko to sa assignment sheet ko]

1. The year is 2146, and Martian Mining & Engineering is building an ore processing plant on the rim of Erebus Crater. You are off on an extended coffee break at the ice cream shop on the far side of the crater, 300 m away, and you can see someone using a hammer back at the plant.
The atmosphere of Mars is essentially pure carbon dioxide (CO2), and the molar masses of carbon and oxygen are 12 g/mol and 16 g/mol, respectively. The ratio of specific heats for CO2 is 1.30. The air pressure is 6.78 mb (millibars), and the air temperature is a balmy (for Mars) –27°C. 1 bar = 106 Pa.
a. It seems odd, but you notice that the hammer hits silently, and the “bang” occurs at the top of every swing. What is the period (number of seconds between hits) of the hammer? If necessary, assume that the period has its longest possible value for this to happen, and the hammer reaches the top of its swing half way between hits.
[4]
b. What mechanical impedance does the Martian atmosphere present to the sound waves propagating through it?
[3]
2. A transmission tower is anchored to the rim of the crater by 1.20-cm diameter steel cables stretched to a tension of 12,000 N. A technician is using a signal generator to test mechanical properties of one of the cables by sending a 125-Hz transverse wave of amplitude 0.300 mm along the cable.
[3]
a. What is the speed of transverse waves on the cable? The density of steel is 7800 kg/m–3. [HINT: It may help to find the mass of a 1-m length of the cable.]
b. What mechanical impedance does the cable offer to these waves?
[2]
[3]
c. What time-averaged power is carried by these waves?
[3]
d. What is the maximum angle that the transverse waves make with the undisplaced cable (i.e., with the equilibrium line for the waves)?
e. The signal generator also produces 125-Hz sound waves in the cable. What is the wavelength of these sound waves? Young’s modulus for steel is 20 x 1010 Pa.

ito sa electrical engg at math

Laplace transform daw:

use laplace transform to find y(t)

y'' + y' + y = 0 and y(0) = 2 and y0(0) = −3
Sorry, economics-business management major po ako. Hindi dahil sa katangahan pero di ko po talaga alam yan. Sorry. Kung economics-related question baka masagot ko pa po :)

[paparagon]

ok lang, di naman lhat kayo tinatanong- na-aasar kasi ako doon sa Mapua vs UST thread. Ang sakit nila manglait basta alam nila na "lower class" (o less prestigious- whatever) *** kalaban nila. lalo na sa mga engg programs nila- masyado nilang pinagyayabang ang kagalingan nila.

gusto ko lang malaman *** may katotohanan *** sinasabi ng mga ungas. kaya to 2nd year level lang mga tanong ko, wala paring sumasagot na MIT o UST.

[flsfnoeraekadad]

ok lang, di naman lhat kayo tinatanong- na-aasar kasi ako doon sa Mapua vs UST thread. Ang sakit nila manglait basta alam nila na "lower class" (o less prestigious- whatever) *** kalaban nila. lalo na sa mga engg programs nila- masyado nilang pinagyayabang ang kagalingan nila.

gusto ko lang malaman *** may katotohanan *** sinasabi ng mga ungas. kaya to 2nd year level lang mga tanong ko, wala paring sumasagot na MIT o UST.
Try asking me economic questions. Haha. About supply and demand :)

Print ko questions mo. Try ko pasagutan sa frosh and upperclassmen friends ko sa College of Engineering :)

[neoreo09]

where else but http://ww.k-university.tk/

[TypeRman]

hahaha daming sumuko ah....samantalang ang daming nagsasagutan sa ibang threds hahaha


olats pala mga schools natin dito pinas hehehehe

[GR8_GUY]

ok lang, di naman lhat kayo tinatanong- na-aasar kasi ako doon sa Mapua vs UST thread. Ang sakit nila manglait basta alam nila na "lower class" (o less prestigious- whatever) *** kalaban nila. lalo na sa mga engg programs nila- masyado nilang pinagyayabang ang kagalingan nila.

gusto ko lang malaman *** may katotohanan *** sinasabi ng mga ungas. kaya to 2nd year level lang mga tanong ko, wala paring sumasagot na MIT o UST.
Don't take those cadre of "wealthy elitists" seriously. They are most likely just hangers-on who try hard acting like they are rich, or frustrated nouveaux riche unable to gain social acceptance with the old money and venting their frustration on the "lower class", or the old rich who are losing control of their "elite" status and trying to hold on to the status quo with spiteful attitude. At any rate, it is worthless to lose your sleep over their kind. A quote from a very rich man: No man can tell whether he is rich or poor by turning to his ledger. It is the heart that makes a man rich. He is rich according to what he is, not according to what he has.

[flsfnoeraekadad]

Don't take those cadre of "wealthy elitists" seriously. They are most likely just hangers-on who try hard acting like they are rich, or frustrated nouveaux riche unable to gain social acceptance with the old money and venting their frustration on the "lower class", or the old rich who are losing control of their "elite" status and trying to hold on to the status quo with spiteful attitude. At any rate, it is worthless to lose your sleep over their kind. A quote from a very rich man: No man can tell whether he is rich or poor by turning to his ledger. It is the heart that makes a man rich. He is rich according to what he is, not according to what he has.
Di ko pa din masagutan. Haha :insane:

I am trying since kaninang umaga.

[Dacs]

Out of curiosity, may sagot na ako sa Laplace problem. However sa iba, nalimutan ko na sila :D

[paparagon]

cool *** una dapat *** madahil kasi plugin formula lang *** mga un- mga waves in fluid lang *** unang question- walang derivatives intergrals at differential equations.

*** pangalawa laplace- alam siguro ng lahat ng engineers (especially *** electrical) at mathematicians *** laplace transforms. cool!

[paparagon]

ito bigay samin para bonus- next week pa pasahan kaya pahingi ng tulong!

solve *** differential equation:

(x^2)*y'' + 22x*y' + 62y = 0

ito pa galing sa physics ko:

P1. The sound level 5.0 cm away from a vibrating harp string is 60 dB.
(a) What is the intensity of the sound 5.0 cm from the string? [1]
(b) What is the acoustic power emitted by the string? [2]
(c) What is the sound level 10 cm away from the string? (Assume absorption is negligible,
and that the length of the string is much greater than 10 cm). [1]
P2. A point source emits 2×10−6 W of sound. A sound engineer measures the sound level 10 m
away from the source and 100 m away. The first reading is 48.9 dB, and the second reading
is 27.9 dB. Based on these readings, what is the absorption coefficient for the medium [2],
and what is the background sound level [2]? (There is a level of background noise present at
all times, and it is the same everywhere).

P5. A wave propagates from medium 1 with impedance Z1 to medium 2 with impedance Z2 < Z1.
A standing wave pattern is measured in medium 1, and the maximum amplitude is found to
be 5 times larger than the minimum amplitude. Calculate the following quantities:
(a) The reflection coefficient. [1]
(b) The transmission coefficient. [1]
(c) Z2/Z1. [1]

[flsfnoeraekadad]

ito bigay samin para bonus- next week pa pasahan kaya pahingi ng tulong!

solve *** differential equation:

(x^2)*y'' + 22x*y' + 62y = 0


Ano yang nasa taas ng y? power? Any clue para masagutan ko yan. Seems madali :D

[Dacs]

Ahehehe

(x^2) * y'' + 22x * y' + 62 * y = 0 [eq 1]

Let u = ln x

so

x = exp (u) [eq 2]

To make the long story short, after applying (2) to (1), it will become:

(D^2 + 21 * D + 62) * y = 0 [eq 3]

Must consider D is a function of u, not of x :)

Sa palagay ko naman, you can solve [eq 3], after solving it, just change u to x :D

[flsfnoeraekadad]

Ahehehe

(x^2) * y'' + 22x * y' + 62 * y = 0 [eq 1]

Let u = ln x

so

x = exp (u) [eq 2]

To make the long story short, after applying (2) to (1), it will become:

(D^2 + 21 * D + 62) * y = 0 [eq 3]

Must consider D is a function of u, not of x :)

Sa palagay ko naman, you can solve [eq 3], after solving it, just change u to x :D
Di ko pa din magets. Mahina talaga utak ko sa math at pure sciences :insane:

[paparagon]

astig ha! iba *** sakin y =x^k *** substitution ko. masmadali (tingin ko).
lol sa totoo lang *** physics question talaga dapat *** madali kasi di masyadong complicado *** math nun

[Dacs]

Search for "Euler-Cauchy Equation" to solve the DE problem

[Madgrunty]

ang haba kasi ng tanong nakakatamad basahin. ETo ece board question
j^j=?
ln(j)=?

where j=imaginary number
simple lang solution nyan.

[flsfnoeraekadad]

ang haba kasi ng tanong nakakatamad basahin. ETo ece board question
j^j=?
ln(j)=?

where j=imaginary number
simple lang solution nyan.
The Breakdown:
a. Imaginary numbers are numbers which value is -j^(1/2) or the square root of negative j.

b. We know that there is no exact value for the square root of any negative number because all square products are positive.

c. Solution for j^j = 0.20787957635076190854695561983498

[paparagon]

lol di ko pa ako board exam level- 2nd year computer engg palang ako!

oo *** isa cauchy-euler type, iba lang method na ginamit ko.

di ko makuha *** j question mahirap- may transform ba akong gagawin?

[flsfnoeraekadad]

lol di ko pa ako board exam level- 2nd year computer engg palang ako!

oo *** isa cauchy-euler type, iba lang method na ginamit ko.

di ko makuha *** j question mahirap- may transform ba akong gagawin?
*** j pala kinuha ko yan sa [-1^(1/2)]^[-1(1/2)] :D

[paparagon]

hindi nag-ma-make sense *** proof mo.

di j = square root of -1

naiisip ko sa ln(j) ay kung *** ln(1) = 0 eh di *** lnj ay 0 din.

*** isa ata naisip ko lang complex operation

[paparagon]

hindi nag-ma-make sense *** proof mo.

di ba j = square root of -1

naiisip ko sa ln(j) ay kung *** ln(1) = 0 eh di *** lnj ay 0 din.

*** isa ata naisip ko lang complex operation

[flsfnoeraekadad]

hindi nag-ma-make sense *** proof mo.

di ba j = square root of -1

naiisip ko sa ln(j) ay kung *** ln(1) = 0 eh di *** lnj ay 0 din.

*** isa ata naisip ko lang complex operation
Ay so mali pala ako? Oo nga, teka try ko ulit solve. :)

[kalteck]

The Breakdown:
a. Imaginary numbers are numbers which value is -j^(1/2) or the square root of negative j.

b. We know that there is no exact value for the square root of any negative number because all square products are positive.

c. Solution for j^j = 0.20787957635076190854695561983498
Using Maples
> [((-1)^1/2)]^[(-1)^1/2] ;

[(-1)/2]

[-1/2]





> (-0.5)^(-0.5) ;

-1.414213562 I

> ln[((-1)^1/2)];

-1

ln[--]

2

[kalteck]

^
> ln[(-1)/2];

-1

ln[--]

2

> ln(-.5) ;

-0.6931471806 + 3.141592654 I

[flsfnoeraekadad]

^
> ln[(-1)/2];

-1

ln[--]

2

> ln(-.5) ;

-0.6931471806 + 3.141592654 I
Nice, nice! :) hindi ko talaga ma-solve on my part.

[flsfnoeraekadad]

Mr./Ms. Threadstarter, pasingit lang po ako ah :D

A clue for interested people who will answer: Just use Two-Point Form of a Linear equation and you'll get this right. This is very easy! :)

1. Sigma Sales Center will supply 400 lampshades at P250 each. The supply is increased to 600 pieces when the unit price is increased by 10%. (a) Set up the supply function. (b) How many pieces will be supplied if the unit price is P300? (c) Find the lowest price at which this item would be supplied.

2. Volume of sales for Perma Ware Products Corporation, which sells plastic canisters at P60 each, is 600 units. When the price per canister decreases by P3, 120 more canisters are sold. (a) Set up the demand function. (b) What is the highest price to be paid for this item? (c) How many canisters would be demanded if they were free?

3. Laguna Liner has analyzed its sales and finds that 5% more of the round trip tickets are bought for every 20% reduction in the price of each ticket. When the price is P40 per round trip ticket, 200 tickets are sold. (a) Determine the demand equation. (b) Find the maximum price to be paid for each ticket.

4. A firm will supply 900 wall clocks at P300 per clock. When the price drops to P100 a piece, the firm refuses to sell its clocks. (a) Determine the supply equation. (b) How many clocks are available when the unit price is P250?

5. State Realty Corporation handles an apartment complex consisting of 100 units. When the rent of each unit is P 4,000 per month, all units are occupied. However, for each P 500 increase per month, there will be 4 vacancies without any possibility of filling them. What is the maximum month rental for each apartment unit?

6. At a unit price of P 3,000, Christian Jewelry will supply 500 college rings. The supply is diminished by 100 rings if the unit price is decreased by 10%. (a) Set up the supply function. (b) What is the lowest price at which the item would be supplied? (c) How many rings will be supplied if the unit price is P 4,600?

7. A footwear company sells ladies’ shoes at P 800 a pair. Fixed costs are P 120,000 and variable costs amount to 50% of the total revenue: (a) Set up the total revenue, fixed cost, and total cost functions. (b) How many pairs of shoes must be sold to recover fixed costs? (c) Find the break-even point.

Tignan naman natin ang kaastigan nyo sa Economics. Hehe.

[jana_atenista]

paparagon,

when in doubt, always choose letter A. for astig.

agree si me! choose A. Choose The Ateneo. oh make that choose T.A. for The Ateneo!

If its from the Ateneo, it must be good.

[paparagon]

di ko alam *** economics- iba talaga *** math. pero mukhang simple- wala kasing differentiation kung linear lang (could be wrong alam ko tawag sa isang form ng differential equation linear). di ko alam *** formula- engg student ako!

[flsfnoeraekadad]

di ko alam *** economics- iba talaga *** math. pero mukhang simple- wala kasing differentiation kung linear lang (could be wrong alam ko tawag sa isang form ng differential equation linear). di ko alam *** formula- engg student ako!
You are on the right track *okay* Just do the point-slope form.

And by the way, the prices and thq quantities are like points on a linear equation :)

[wArThOg]

payabangan to the highest level dito! hehe

[flsfnoeraekadad]

payabangan to the highest level dito! hehe
Oh eh at least makikita natin yung may ibubuga dito. Hehe. Yan, tulad nyan, wala talaga akong ibubuga sa math saka sa physics/chemistry :lol:

[gold_inhinhiero]

Pasolve naman nito, very basic lang.. wag gagamit ng calculator:

e^(i)(pi)

where e=base of the natural logarithm, i=squareroot of -1, pi=3.1415....

Yun lang :)

[Dacs]

exp(pi * i) = cos(pi) + i * sin(pi)
= -1 + i * 0
= -1

[flsfnoeraekadad]

exp(pi * i) = cos(pi) + i * sin(pi)
= -1 + i * 0
= -1
DACS Hanep! Pinakitaan mo ako ng salitang Brilliance dun! Mapuan Boy ka ba? :D hanep talaga kayo sa matematika. :lol:

[panatikongtunay]

exp(pi * i) = cos(pi) + i * sin(pi)
= -1 + i * 0
= -1

ayus ah!!!tama ba ako na Euler's identity ito????

[gold_inhinhiero]

^^ yep.. Euler's identity.. hehe.. favorite ko sa lahat.. :)

Eto next:

Proving: Very Basic lang: You cannot extract the zeros of polynomial functions with a degree greater than 5 using a formula. (First Prove was given by Henrik Abel)

[gold_inhinhiero]

Eto pa, mga basic questions lang:

Physics: A particle (mass is m and charge is greater than zero) moves in a region where both the electric and magnetic fields are uniform and given E=Eoi and B=Boi where Eo and Bo are positive quantities. At t=0 the position and velcity of the particle are ro (o subscript) = 0 and vo (o subscript)=voj.

Determine the position and velocity of the particle at the time t=(pi)/qBo.

Determine the motion of the particle for t>0.

Determine the kinetic energy of the particle as a function of time t for t>0.


Chemistry:
Find the osmotic pressure of an aqeuos H2SO4 solution if the weight of H2SO4 is 24g and the solution is set at 10 degree celsius. Assume 1 liter of the solution.

Biology:
Determine the possible blood types of a child, if his mother has an AB type, and his father is O type.

Math:
Find the equation of the plane tangent to the sphere of equation x^2 + y^2 + z^2 = 12 at point (2,2,2).

Yun lang hanggang diyan lang. :)

[paparagon]

yep- euler's identity.

dacs pahinging tulong:

bigyan mo ako ng algorithm para solve *** pi (para sa computer)
kahit formula lang di na *** code.

[paparagon]

tindi vector calculus/algebra. *** physics ata ma-cro-cross product pero mukhang may kulang na info. gusto ko malaman *** orientation ng particle. (dapat may picture para mas madali i visualize).

chem - hanggang vapour pressures lang chem ko- di naman ako chem engg.

bio ganon din sa bio- di ako biologist

math- damn di ko matandaan *** gagawin. naiisip ko mag-pa-partial derivative para makuha *** lines. tas gagawing plane nalang kasi un ata *** definition ng plane-dalawang lines na gumagawa ng surface.

di nalang ba pwedeng differential equations *** tanong mo? mas alam ko un kaysa vector algebra/calculus

[Dacs]

yep- euler's identity.

dacs pahinging tulong:

bigyan mo ako ng algorithm para solve *** pi (para sa computer)
kahit formula lang di na *** code.

Heto yung formula:

http://img.photobucket.com/albums/v208/DeDBoL/tan.jpg

Use x = 3^(1/2) / 3 and you should expect to get an inverse tangent value of pi / 6

Madali lang yan gawan ng algorithm. To give you an idea, I did one when I was in HS :D

And I'm not from Mapua :)

[Dacs]

Osmotic Pressure:

http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/imgkin/osmop.gif

n = 24g / (98g /mol) = 0.24490 mol
V = 1 L
R = 0.0821 (L-atm)/(mol - K)
T = 273.15 + 10 = 283.15 K

P = (0.24490)(0.0821)(283.15)/(1) = 5.69 atm

[Dacs]

Possible Blood Types:

Genotype of Type AB: AB
Genotype of Type O : OO

\ A B
O AO BO
O AO BO

So possible combinations would be AO (Type A) and BO (Type B)

So kung kayo guys ay Type O at may anak kayong Type AB, nakow! Nasalisihan kayo! :D

[Dacs]

Tangent:

I think (correct me if I'm wrong, it has been quite a while since I took up multivariable calculus) the equation is

T(x,y,z) = 2 * (x - 2) + 2 * (y - 2) + 2 * (z - 2)

since P = (2,2,2) and it has a normal vector of <2,2,2>

[gold_inhinhiero]

Nice Dacs.. napapahanga mo ko lahat yata ng fields of study alam mo.. Oh well, sana maachieve ko rin lahat ng nagawa mo.. :)

[gold_inhinhiero]

Dacs ikaw yung 6th placer sa Chem Eng'g Board diba and Summa sa UP?

[Dacs]

Magna ako... magna nine years! Seriously, nine years ako sa college :D

Uu ako yung 6th nung November 2005 ChE board

[flsfnoeraekadad]

Tangent:

I think (correct me if I'm wrong, it has been quite a while since I took up multivariable calculus) the equation is

T(x,y,z) = 2 * (x - 2) + 2 * (y - 2) + 2 * (z - 2)

since P = (2,2,2) and it has a normal vector of <2,2,2>
Dacs hanep! Buwahahaha. The PExMan. Turuan mo ko Mathematical Economics pag nahihirapan ako ah :lol:

[gold_inhinhiero]

@Dacs: Ok lang yun kasi 2 degree naman natapos mo right? Hehe.. Ang galing mo! Siguro lahat ng quizzes and tests mo laging perfect or kung di man yung pinakamarami mong possible na mali ay 5.. Well kakainggit ka.. :)

[panatikongtunay]

yan!!!!ito dapat ang ginagawa sa Academe!!!!astig talaga itong thread na ito...

Dacs:talaga namang elibs ako sa iyo!sana marami pang tulad mo dito sa forum...galing talaga!!!!!!!

[Dacs]

Anu ba kayo? Bulakbol ako nung college. Isa lang ang degree ko (BSChE) :) and it took me 9 long years :D

Marami akong 5.0 sa TOR ko hahaha

Kaya nga sinabi ko sa isang thread na dapat may focus kayo sa studies. If I could go back in time, magaaral ako ng maigi. Not that I regret anything with my college life, after all, you cannot appreciate the beauty if you don't see the uglier side of life ;)

[ubermensch]

^^ yep.. Euler's identity.. hehe.. favorite ko sa lahat.. :)

Eto next:

Proving: Very Basic lang: You cannot extract the zeros of polynomial functions with a degree greater than 5 using a formula. (First Prove was given by Henrik Abel)

Astig nga nung Euler's identity, lalo na nung pinoint-out sa amin ng teacher namin na when it is written as e^(i*pi)+1=0, you have in one equation 5 of the most basic constants in mathematics: e, i, pi, 1 and 0.

Dun sa polynomial question mo, I think it should be "greater than or equal to 5". I guess you took Galois Theory :)

[xybert_22]

ito bigay samin para bonus- next week pa pasahan kaya pahingi ng tulong!

solve *** differential equation:

(x^2)*y'' + 22x*y' + 62y = 0

[1]

(x^2)*y'' + 22x*y' + 62y = 0

d^2y/dx^2 + 22 dy/dx + 62y = 0

D^2 +22D + 62 = 0

change D to m

m^2 +22m + 62 =0

solve for the value of m.

m= sqrt(59)+11 = 18.68, sqrt(59)-11=-3.32


y= C1 e^(18.68t) + C2 e^(-3.32t)

[Dacs]

(x^2)*y'' + 22x*y' + 62y = 0

d^2y/dx^2 + 22 dy/dx + 62y = 0

D^2 +22D + 62 = 0

change D to m

m^2 +22m + 62 =0

solve for the value of m.

m= sqrt(59)+11 = 18.68, sqrt(59)-11=-3.32


y= C1 e^(18.68t) + C2 e^(-3.32t)

See the item in bold. Panu nangyari yung transformation? Bigla nawala yung x?

[paparagon]

mali ata! *** solution dapat sa cauchy-euler type hindi exponential. dapat polynomial *** solution.

[Dacs]

^Kaya nga. Kelangan mo ng variable substitution dyan (u = ln (x)). I think I presented the solution before (nasa page 1 ata)

[xybert_22]

Ah OK. Try ko po ulet.


x^2y”+ 22xy’+ 62y = 0

Let x = e^t, t=lnx

Since Ax^2y” + Bxy’+Cy = f(x); is equal to A(d^2y/dt^2 ) + (B-A)dy/dt + Cy =f(e^t) using Cauchy- Euler Equation.

Therefore

x^2y”+ 22xy’+ 62y = 0 is equal to (d^2y/dt^2 ) + 21dy/dt + 62y =0.

Simplify the equation:

y’=dy/dt

therefore the equation is

y”+21y’+62y=0

solve for homogenous Solution

m^2+21m+62 =0

solve for m

m = -10.5 + (48.25)^1/2 , -10.5 – (48.25)^1/2;
m= -3.55, -17.44

Yh= C1 e^(-3.55t) + C2 e^(-17.44t)

Solve for particular solution

Yp = 0 since the equation is equal to 0.

Solve for total solution

Yt = Yh + Yp

Yt = C1 e^(-3.55t) + C2 e^(-17.44t) + 0

Yt = C1 e^(-3.55t) + C2 e^(-17.44t)

But x = e^t, and t = lnx

Therefore

Yt = C1 (-3.55 X)+ C2 (-17.44X)

[xybert_22]

mali ata! *** solution dapat sa cauchy-euler type hindi exponential. dapat polynomial *** solution.

Bro, Sa University of Calgary ka ba nag-aaral?

[flsfnoeraekadad]

Ah OK. Try ko po ulet.


x^2y”+ 22xy’+ 62y = 0

Let x = e^t, t=lnx

Since Ax^2y” + Bxy’+Cy = f(x); is equal to A(d^2y/dt^2 ) + (B-A)dy/dt + Cy =f(e^t) using Cauchy- Euler Equation.

Therefore

x^2y”+ 22xy’+ 62y = 0 is equal to (d^2y/dt^2 ) + 21dy/dt + 62y =0.

Simplify the equation:

y’=dy/dt

therefore the equation is

y”+21y’+62y=0

solve for homogenous Solution

m^2+21m+62 =0

solve for m

m = -10.5 + (48.25)^1/2 , -10.5 – (48.25)^1/2;
m= -3.55, -17.44

Yh= C1 e^(-3.55t) + C2 e^(-17.44t)

Solve for particular solution

Yp = 0 since the equation is equal to 0.

Solve for total solution

Yt = Yh + Yp

Yt = C1 e^(-3.55t) + C2 e^(-17.44t) + 0

Yt = C1 e^(-3.55t) + C2 e^(-17.44t)

But x = e^t, and t = lnx

Therefore

Yt = C1 (-3.55 X)+ C2 (-17.44X)
Di ko maintindihan! Bwahahahaahha :lol: Anong subject ba ma-ttake up yan?

[Madgrunty]

ang haba kasi ng tanong nakakatamad basahin. ETo ece board question
ln(j)=?
j^j=?


where j=imaginary number
simple lang solution nyan.

post ko lang solusyon. The first time i encountered this question, i got really excited. the key is to apply euler equation. i.e. exp(j*pi)=-1
Pakisabi na lang kung may mali.

1.
let ln(j)=a
j=exp(a) <- square both sides
-1=exp(2a) <-apply euler on -1
exp(j*pi)=exp(2a)
j*pi=2a
a=pi*j/2
hence ln(j)= pi*j/2

2.
let a=j^j
ln(a)=jln(j)
ln(a)=j*pi*j/2 <-from(1)
ln(a)=-pi/2
a=exp(-pi/2)
hence j^j= exp(-pi/2)

[xybert_22]

Elementary Differential Equation. Di ako sure kung tama yan kasi tagal ko ng kinuha *** subject na yan. Yan n lang *** natatandaan ko.

[paparagon]

xybert_22- oo taga u of c ako! taga u of c kadin ba? kita tayo! pm mo lang ako.

flsfnoeraekadad- lahat ng engg students dapat malaman yun kaya pag-engg ka sigurado mga 4+ courses mo sa calculus- ito *** isa sa mga doon.

naging magulo na nga *** circuits dahil dyan sa mga equation na yan.

[flsfnoeraekadad]

xybert_22- oo taga u of c ako! taga u of c kadin ba? kita tayo! pm mo lang ako.

flsfnoeraekadad- lahat ng engg students dapat malaman yun kaya pag-engg ka sigurado mga 4+ courses mo sa calculus- ito *** isa sa mga doon.

naging magulo na nga *** circuits dahil dyan sa mga equation na yan.
Buti na lang pala di ako nag-Eng'g sa school ko. Kundi ma-aaral ko din yan. Kahirap uy paparagon :lol:

[xybert_22]

xybert_22- oo taga u of c ako! taga u of c kadin ba? kita tayo! pm mo lang ako.

flsfnoeraekadad- lahat ng engg students dapat malaman yun kaya pag-engg ka sigurado mga 4+ courses mo sa calculus- ito *** isa sa mga doon.

naging magulo na nga *** circuits dahil dyan sa mga equation na yan.

Taga mapua po ako. May kapatid ako na taga CALGARy, sa SAIT ng-aaral. Kung makakapunta rin ako ng CANADA malamang jan din ako mag-aaral. HOPe so. :)

Favorite ko nga *** circuits nyan eh. Lalo na *** ginagamit sa CONTROL system.

[paparagon]

astig ha! gusto ko pa ng mga kasamang pilipino sa school. maunti lang kami sa engg school ng u of c. as in 3 lang ata kami (*** nakakatagalog pa- di ko binibilang *** whitewash kahit masarap silang kasama).

basta pag-nasa calgary kana, apply ka agad sa u of c. tulungan kita.