Thread: How Do I solve this (using rolle's)?!?! (sin2pi*x) on -1,1 interval(TESTPREP PLZHELP)

How Do I solve this

Sin2πx [-1,1]

Yes continuous
Yes differentiable
f(-1) = f(1)

So now derive

2cos2πx = 0

How do I solve this? The answer in my book says +/- 1/4, +/- 3/4

How

Originally Posted by skinsdomination09

How Do I solve this

Sin2πx [-1,1]

Yes continuous
Yes differentiable
f(-1) = f(1)

So now derive

2cos2πx = 0

How do I solve this? The answer in my book says +/- 1/4, +/- 3/4

How

I am going to have to GUESS what the question is....

I am assuming that you are trying to find the points in where

If so you need to solve the equation



Taking the arccosine of both sides gives





This will generate all of the solutions to the problem.