Answer: (a)- 
Step-by-step explanation:
Given
Central angle is 
The radius of the unit circle is 
Arc length is given by

Put the values

4, 4+4 is 8 which is double of 4
For a function to have a derivative in a point has to be continuous at the point, that is, it has to be defined at that point, other wise the derivative would be meaningless.
What is the "in" for in your equation? Repost.
Answer: -623,397
Step-by-step explanation: