Question

How do you solve `0=1/2cos2x` between 0 and 2pi?

Answer 1

`x=pi/4 or 3pi/4 or 5pi/4 or 7pi/4`

Explanation:

`(1/2)cos2x=0` means

`cos2x=0`.

But within the domain `[0,2pi]`, cosine of an angle is zero for `2x=pi/2`, `2x=3pi/2`, `2x=5pi/2` and `2x=7pi/2`.

Hence `x=pi/4 or 3pi/4 or 5pi/4 or 7pi/4`