#### Hckyplayer8

##### Junior Member

- Joined
- Jun 9, 2019

- Messages
- 94

The specific question I'm working on is

Suppose f(x) = x^3 cos x

(a) Use the differentiation rules to compute f prime (x).

(b) Find an equation for the line tangent to the graph of f at x = π.

Okay so the first part seems pretty simple. Got the power rule down and while the proof of the trig rule was a tad daunting, I'm fine with memorizing that the derivative of cosine is negative sine.

So for part (a) I have 3x^2 - sin x . Looking at that I feel like I am done. The product rules doesn't look like an option cause it's just a single function.

So pending I'm done with (a), (b) looks like it is asking for point slope form. It is here that my understanding breaks down. I'm not even sure where to begin.