Advertisements
Advertisements
Question
If tan θ = `1/sqrt5` and θ lies in the first quadrant then cos θ is:
Options
`1/sqrt6`
`(-1)/sqrt6`
`sqrt5/sqrt6`
`(-sqrt5)/sqrt6`
Advertisements
Solution
`sqrt5/sqrt6`
APPEARS IN
RELATED QUESTIONS
Prove that:
Express each of the following as the product of sines and cosines:
sin 2x + cos 4x
Prove that:
cos 80° + cos 40° − cos 20° = 0
Prove that:
cos 20° + cos 100° + cos 140° = 0
Prove that:
If cos (α + β) sin (γ + δ) = cos (α − β) sin (γ − δ), prove that cot α cot β cot γ = cot δ
If y sin ϕ = x sin (2θ + ϕ), prove that (x + y) cot (θ + ϕ) = (y − x) cot θ.
If (cos α + cos β)2 + (sin α + sin β)2 = \[\lambda \cos^2 \left( \frac{\alpha - \beta}{2} \right)\], write the value of λ.
If sin A + sin B = α and cos A + cos B = β, then write the value of tan \[\left( \frac{A + B}{2} \right)\].
Prove that:
`(cos 7"A" +cos 5"A")/(sin 7"A" −sin 5"A")` = cot A
