Absolute Extrema of Trigonometric Functions on Closed Intervals

[joonpark89]

Homework Statement

Find the absolute max and absolute min values of function on the given interval:
f(t) = 2cos(t) + sin(2t), [0,pi/2]

Homework Equations

The Attempt at a Solution

f '(t) = 0
0 = -2sin(t) + 2cos(2t)
2sin(t) = 2cos(2t)
stuck...

 

[BSMSMSTMSPHD]

Use a double angle formula to change the cosine term into a sine term. Then you'll have solvable equation.