Question

If `sintheta=a/b`, then `costheta` is equal to
A. `b/(sqrt(b^(2)-a^(a))`
B. `b/a`
C. `(sqrtb^(2)-a^(2))/b`
D. `a/(sqrt(b^(2)-a^(2))`

Answer 1

Correct Answer - C
Given, `sintheta=a/b` `[therefore sin^(2)theta+ cos^(2)theta=1 rArr costheta=sqrt(1-sin^(2)theta)]`
`therefore costheta=sqrt(1-sin^(2)theta)`
`=sqrt(1-(a/b)^(2)) = sqrt(1-a^(2)/b^(2))= (sqrtb^(2)-a^(2))/b`