Question

Evaluate sin(Arcos(-9/√145))

Answer 1

Answer: $\frac{8}{\sqrt{145}}$

We have the following expression:

$sin(arcos(-\frac{9}{\sqrt{145}}))$

First we have to solve the inner parenthesis:

$sin(arcos(-0.747))$

Then the second parenthesis:

$sin(138.366)=0.664$

According to the options given, the only expression that fulfills the value of $0.664$ is:

$\frac{8}{\sqrt{145}}=0.664$