Question

what is the particular solution for this differential equation y''''+y''=x^4

Answer 1

try let y=Ax^4+Bx^3+Cx^2+Dx+E

Answer 2

i did that sir it does not work

Answer 3

all
the coefficients can not be solved for by using that polynomial

Answer 4

i would prefer u
http:/www.wolframalpha.com

Answer 5

hmmmmm

Answer 6

yp=ax^6+bx^5+cx^4+dx^3+ex^2+fx+g

Answer 7

@ ictrees you must be at school already! get to class

Answer 8

Still say set y'' = z so y'''' = z'', make life simpler...

Answer 9

u sayin use laplace?

Answer 10

No, u just looking for generic solution, not ivp, right?

Answer 11

yea...just generic
i need to know what method i need to use...

Answer 12

ohh

Answer 13

why ohhh?

Answer 14

nothingohhh

Answer 15

ok

Answer 16

So to get the complementary u solve the auxiliary (for the reduced equation)

I think...

Answer 17

i used yp = Ax^4+Bx^3+Cx^2+Dx+E, but the Dx part is repeated from complementary solution so you have to multiply it by X^2 to get rid of that repeating solution..i even plugged my solution in and checked it worked out perfect

Answer 18

for those that are curious the full solution is y=c1+c2x+c3cosx+c4sinx+(1/30)(x^6)-(x^4)+(12)(x^2)

Answer 19

I see complementary (for reduced) is just c1 sin + c2 cos (lambda = +-i) and Wolfram then gives

x^4-12x^2 +24 then you can integrate twice to get back to your equation.

Answer 20

what is wolfram?

Answer 21

http://www.wolframalpha.com/input/?i=y%27%27%2By%3Dx^4

Answer 22

btw estudier this is not a second order equation its a fourth order equation and other term is second order

Answer 23

Sure but u can set z = y'' to convert to second order then just integrate twice at the end.

Answer 24

U can see it comes out the same, no?

Answer 25

no sir...

Answer 26

Why not...?

Answer 27

the zero solutions are missed out if u transform the equation

Answer 28

The solution u get is the same as the solution u gave....

Answer 29

i cannt uderstand the qus also :(

Answer 30

is it1/30 x^4-x^2-12