Ask your own question, for FREE!
Mathematics 16 Online
OpenStudy (itz_sid):

Help Pleeeees :3

OpenStudy (itz_sid):

I need help with Numero Cuatroo. (#4).

OpenStudy (itz_sid):

@agent0smith

OpenStudy (sissyedgar):

I don't know. Sorry! ♥

OpenStudy (agent0smith):

Not sure, sorry.

OpenStudy (itz_sid):

It's okay guys. :/

OpenStudy (emilee02):

im sorry idk

OpenStudy (karim728):

what university u go too?

OpenStudy (518nad):

ill hlep u lol xD

OpenStudy (518nad):

first rewrite it in standard form for me dy/dx + p(x) y = q(x)

OpenStudy (seratul):

518nad always comes in clutch.

OpenStudy (itz_sid):

@Karim728 I go to CSULB.

OpenStudy (itz_sid):

Okay, I get... \[\frac{ dy }{ dx } -\frac{ 4 }{ x }y = 6x^3e^x\]

OpenStudy (518nad):

okay so here is how this method works

OpenStudy (itz_sid):

\[I(x) = e^{\int\limits \frac{ 4 }{ x } dx}\]

OpenStudy (itz_sid):

Negative*

OpenStudy (518nad):

we try to multiply by some func u(x) such that y'u(x) + p(x)u(x) y = q(x)u(x) (Y*u )' = y'*u + y*u' = y' u + p u y = q u this means u' = p u so u = e^(int(p) dx) this u is the integrating factor

OpenStudy (itz_sid):

Yessir.

OpenStudy (518nad):

if we do this then (Y*u )' = qu y= (integral qu dx )/ u

OpenStudy (518nad):

oh dont forget the -4/x

OpenStudy (518nad):

u are doing 4/x

OpenStudy (itz_sid):

So then Integrating Factor = x^4 \[\int\limits[x^4y]' = \int\limits 6x^7e^x\]

OpenStudy (itz_sid):

Oops. forgot the negative. lol

OpenStudy (518nad):

yes

OpenStudy (518nad):

tell me whatu get

OpenStudy (itz_sid):

\[I(x) = e^{-4 \int\limits \frac{ 1 }{ x }dx} = e^{\ln|x|^{-4}} = x^{-4} = \frac{ 1 }{ x^4 }\] Thus \[\int\limits [\frac{ 1 }{ x^4 }y]' = \int\limits \frac{ 6 }{ x } e^x\]

OpenStudy (518nad):

yup

OpenStudy (518nad):

so itsss the last choice

OpenStudy (itz_sid):

Oh i see. Haha thanks!

OpenStudy (emilee02):

hey could you un tag me so i can stop getting notified

OpenStudy (emilee02):

ab this quistion

OpenStudy (sissyedgar):

Well that looked difficult... You two were talking like it was common conversation or something... xP I was just sitting like "What in the World......"

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!