Basic derivative

[Frogger888]

Ok I have spent 20 minutes on a simple derivative

x*(e^(3x))

here is what I get using the chain rule

1st derivative 3e^3x
2nd derivative 9e^3x

what am I doing wrong I am having a serious brain fart

I am trying to solve a 2nd order diff eq using annihilator but am stuck on this lousy derivative

 

[Unco]

Use the product rule, Frogger.

 

[tkhunny]

x*(e^(3x))

It looks like you are missing the "Product Rule" portion of the problem.

(d/dx)(x*e^(3*x)) = x*(3*e^(3*x)) + e^(3*x)*1 = [e^(3*x)]*(3x+1)

 

[Frogger888]

Thanks guys; it has been 2 years since I have seen this stuff; I better work on my review a little more