Mathematics

Problem

\sin \theta = \frac{\sqrt{5}}{5}

in the first quadrant, then select the correct option/(s) from the following options. (May have multiple correct answers) a. A

\cos \theta = \frac{2\sqrt{5}}{5}

b. B

\tan \theta = \frac{1}{2}

c. C

\cot \theta \times \cos \theta = \frac{4\sqrt{5}}{5}

d. D

\cos \theta = \frac{10}{\sqrt{5}}