If $sinx=1/4$ and $tanx$ is positive, find $cosx$ ?

Question

5261 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-03-01T08:20:26

$cosx=sqrt15/4$

As $sinx$ and $tanx$ both are positive, $x$ lies in Quadrant 1 and $cosx=sinx/tanx$ too is positive.

Hence, $cosx=sqrt(1-sin^2x)=sqrt(1-(1/4)^2)=-sqrt(1-1/16)=-sqrt(15/16)=sqrt15/4$

If sinx=1/4sinx=1/4 and tanxtanx is positive, find cosxcosx?