Question

If tan x=a/4 and cos x=4/b what is the value of sin x?

Answer 1

$cos(x) = \frac{4}{b} \\ \\ tan(x) = \frac{sin(x)}{cos(x)} = \frac{a}{4} \\ \\ substitute... \frac{4}{b} ...for ...cos(x) \\ \\ \frac{sin(x)}{ \frac{4}{b} } = \frac{b*sin(x)}{4} = \frac{a}{4} \\ \\ b*sin(x) = a \\ \\ sin(x) = \frac{a}{b}$