Critical numbers of Trig?

1. The problem statement, all variables and given/known data


3. The attempt at a solution
I found the derivative and set it equal to zero and to reduce writing I substituted x for theta

My question is what are the critical numbers? do the critical numbers exist where sec(x) is underfined because sec(x) will never equal 0.


Homework Helper
The expression can be further simplified:
\sec^{2}x(2\sin x+1)=0
as sec(x) is never zero, we can divide through by it and not loose any solutions. What are you left with?
[tex] sec(x)[2tan(x)+sec(x)] = 0[/tex]

You are trying to find an x to make the left side equal to 0.

Like you said, there is no x for which [tex]sec(x) = 0[/tex], so you can discard that possibility.

How else can the left side of that equation be 0?

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