Question

Evaluate sin(Arcos(-9/√145)).

Answer 1

Use the fact that $\sin x = \sqrt{1-\cos^2 x}$ to solve it.

$\sin(\arccos(-\frac{9}{\sqrt{145}}))=\sqrt{1-\cos^2(\arccos(-\frac{9}{\sqrt{145}}))} =\\= \sqrt{1-(-\frac{9}{\sqrt{145}})^2}=\frac{8}{\sqrt{145}}$

Answer 2

Answer:

a

Step-by-step explanation: