Answer:
[tex]x = \frac \pi4 + k\pi (k \in \mathbb{Z})[/tex]
Step-by-step explanation:
If [tex]cos\ x = 0 \rightarrow sin\ x = \pm1[/tex], which is obviously not a solution. At this point we can divide both sides by [tex]cos\ x[/tex] to get
[tex]\frac {sin\ x}{cos\ x} = 1 \rightarrow tan\ x = 1[/tex]
which has solutions [tex]x = \frac \pi4 + k\pi (k \in \mathbb{Z})[/tex]
