- #1
Feodalherren
- 605
- 6
Homework Statement
y′′=−20⋅4x^3
Homework Equations
Undetermined coefficients method
The Attempt at a Solution
so at first, solving the associated homogeneous equation I find the fundamental set of solutions to be: y1=1 and y2=x.
I know that these are correct. Now for the part that confuses me.
I'm trying to find Yp, the particular solution.
g(x) = -80x^3 so Yp is of the form Ax^3 + Bx^2 + Cx + D
but when I solve this I get Yp=0, that is not correct.
It seems to me that Ax^3+Bx^2+Cx+D is Linearly independent from y1 and y2 so why doesn't this work? The book lists the solution as Yp=-4x^5.