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**[SOLVED] Tough Diff EQ problem**

**1. Homework Statement**

y^(4)-8y^(2)-9y=7e^(-3x)

y^(4)=fourth derivative, y^(2)=second deriv.

**2. Homework Equations**

Need to find complimentary solution and particular solution using variation of parameters

**3. The Attempt at a Solution**

r^4-8r^2-9=0

(r^2-9)(r^2+1)=0, r=9,-1

Y(c)=Ce^(9x)+Ce^(-x)

I think the comp soln is right, but I am unsure on how to start on Y(p)