Posted by Kris on .
I'm trying to find the second derivative of h(x)= x^2 + cos(kx)
My answer for h'(x) is 2x  ksin(kx) but I'm not sure if that's right.
Then the answer I got for h''(x) was h''(x) = 2  k^2cos(kx) but I'm pretty sure that's wrong based on the graph I was given.
Is my answer for the first derivative right? Thanks!

Calculus AB 
Kris,
Oh nevermind, something was just set weird on my calculator that was throwing the graph off. I reset it and it looked like it was supposed to.