I need to find the slope of the graph of the function at the given point.

Question

Function:
f(theta)=4sin(theta)-(theta)

Point:
(0,0)

I tried finding the derivative of the function at theta=0, but I got 0 for an answer.

I checked the answer in the back of my book and it is 3.

I just need to figure out how to get there.

Thanks to anyone who tries to help me.

--Cori

Answer 1

The derivative of f(theta) is
f'(theta) = 4 cos(theta) -1
When theta = 0, the value of the derivative is 4 -1 = 3.

Answer 2

Only one question: How did you get -1 from -theta ?

Thanks so much!

Answer 3

The derivative of f(thetha) = theta is
f'(theta) = df/d(theta) = 1. It's the same thing as saying the derivative of
f(x) = x is f'(x) = 1.

Answer 4

Thanks so much. I get it now.