Question

Solve the initial value problem y''+9y=0 when y(0)=2 and y'(0)=3. Can't seem to get the correct answer, help would be appreciated

Answer 1

what is your characteristic equation?

Answer 2

well it wil be y=c1*e^(m1*x)+c2e^(m2*x). The roots are m1=0 and m2=-9, but I can't get the correct values for c1 and c2...

Answer 3

your roots are wrong

Answer 4

m^2 + 9 = 0

m^2 = -9

m = 0 +- 3i

Answer 5

ah, missed a sign somewhere

Answer 6

y = e^0 (c1 cos(3x) + c2 sin(3x))

y = c1 cos(3x) + c2 sin(3x)

Answer 7

Got the rest of it , thanks a bunch