Question

Find an angle x where sin x = COS x.

Answer 1

Answer:

$x = \frac \pi4 + k\pi (k \in \mathbb{Z})$

Step-by-step explanation:

If $cos\ x = 0 \rightarrow sin\ x = \pm1$, which is obviously not a solution. At this point we can divide both sides by $cos\ x$ to get

$\frac {sin\ x}{cos\ x} = 1 \rightarrow tan\ x = 1$

which has solutions $x = \frac \pi4 + k\pi (k \in \mathbb{Z})$