# Higher order Derivative Ques

• Jan 11th 2010, 02:19 PM
Higher order Derivative Ques
show that the equation $f" (x) + 4 f'(x) + 4 f(x) = 0$ is satisfied if $f(x) = (3x-5)e^-2x$

What is this question asking me to do? I know I will need to find the first and second derivative but where does the + 4 part fit in?
• Jan 11th 2010, 02:34 PM
Henryt999
Quote:

show that the equation $f" (x) + 4 f'(x) + 4 f(x) = 0$ is satisfied if $f(x) = (3x-5)e^-2x$

What is this question asking me to do? I know I will need to find the first and second derivative but where does the + 4 part fit in?

Find the y'' and y'.
Then y'' + 4 y' + 4y = 0 So one y'' four of those y' and four y:s must give you 0