Question

if sin beta =a/b,then cos beta is equal to ____​

Answer 1

$\sin\beta = \frac{a}{b}$

We know,

$\text{sinθ = } \sf\frac{perpendicular}{hypotenuse} \\ \\ \rm base = \sqrt{ {(hypotenuse)}^{2} - {(perpendicular)}^{2} } \\ \rm base = \sqrt{ {b}^{2} - {a}^{2} }$

And,

$\text{cosθ = } \sf \frac{base}{hypotenuse} \\ \\ = > \cos\beta = \rm \green{ \frac{ \sqrt{ {b}^{2} - {a}^{2} } }{b} }$