Answer:
A and B
Step-by-step explanation:
You can take a look at a unit circle to find the solution to this problem (see below).
[tex]\cos^{-1}\left( \dfrac{\sqrt{2}}{2} \right)= \\\\\\\pm \dfrac{\pi}{4}= \\\\\\\dfrac{\pi}{4}, \dfrac{7\pi}{4}[/tex]
Hope this helps!
