Question

How do you solve `ln(cosx)=0` in the interval [0,360]?

Answer 1

`x= 0` or `360` for `x in (0, 360)`

Explanation:

`ln(cosx) =0`

`cosx = e^0 -> cosx=1`

Hence: `x=arccos(1)`

Since: `arccos(1) = 0` and `2pi in (0, 2pi)`

Therefore, in degrees: `x= 0` or `360` for `x in (0, 360)`