Question

Please Help!!!!!
If secθ = 4, then sinθ = _____.

Answer 1

Knowing that
`\sec x=(1)/(\cos x)`:


`\sec\theta=4\iff(1)/(\cos\theta)=4\iff\cos\theta=(1)/(4)`

Using that
`\sin^2x+\cos^2x=1`:


`\sin^2\theta+((1)/(4))^2=1\iff \sin^2\theta=(15)/(16)\iff\\\\\boxed{\sin\theta=\pm(√(15))/(4)}`