Question

Evaluate the following :
$\frac{cos20}{sin70}$

Answer 1

We have $\sin (90-\theta )=\cos \theta$

therefore,

$\sin 70=\sin (90-20)=\cos 20$

To evaluate,

$\frac{\cos 20}{\sin 70}$

$=\frac{\cos 20}{\cos 20}$

$=1$