Question

а 14. If sin = a/b then cos is equal to ​

Answer 1

GIVEN

Sin = a/b

TO FIND

Cos =?

To find Cos we have to know the adjacent Side so,

By using the Pythagoras theorem,

a^2 + x^2 = b^2

Now, x^2 = b^2 - a^2

So, Cos = b^2 - a^2/b

ANSWER

Cos = b^2 - a^2/2

$cos = b {}^{2} - a {}^{2} \div 2$