# Math Help - Derivaties of trigonometric functions and natural logs.

1. I gave it a spin, but I'm not sure if I did it correctly. Here is my work.

2. Originally Posted by FullBox
I gave it a spin, but I'm not sure if I did it correctly. Here is my work.
That's correct!

$\displaystyle \frac{d^2}{dx^2}\left[5x\cos(x^2)\right] = -30x\sin{x^2}-20x^3\cos{x^2}$.

3. Thanks for all the help and patience man, I truly appreciate it!

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