Equation Solving: sin(x) - cos(2x) = 0

[reddawg]

Homework Statement

0 = sin(x) - cos(2x)

Original problem asks to find the critical numbers of f(x) = 2cos(x) + sin(2x) . . . above is its derivative simplified and what I need to solve.

 

[epenguin]

Homework Statement

0 = sin(x) - cos(2x)

Original problem asks to find the critical numbers of f(x) = 2cos(x) + sin(2x) . . . above is its derivative simplified and what I need to solve.

Have you ever seen cos2x in any formula?

 

[reddawg]

Yes...

cos2x=1-2sin^2(x)

I can use that to my advantage I realizes...