Advertisements
Advertisements
Question
Find the value of sin 75°.
Advertisements
Solution
sin 75°
= sin (45° + 30°) = sin 45° cos 30° + cos 45° sin 30°
[∵ sin (A + B) = sin A cos B + cos A sin B]
`= 1/sqrt2 xx sqrt3/2 + 1/sqrt2 xx 1/2`
`= (sqrt3 + 1)/(2sqrt2) xx sqrt2/sqrt2`
`= (sqrt6 + sqrt2)/4`
APPEARS IN
RELATED QUESTIONS
Find the value of the following:
cot 75°
Find the value of the following:
`sin pi/4 cos pi/12 + cos pi/4 sin pi/12`
Prove that 2 tan 80° = tan 85° – tan 5°.
Prove that:
sin(A + 60°) + sin(A – 60°) = sin A.
Prove that:
tan 4A tan 3A tan A + tan 3A + tan A – tan 4A = 0
If sin A = `12/13`, find sin 3A.
If tan x = `3/4` and `pi < x < (3pi)/2`, then find the value of sin `x/2` and cos `x/2`.
Prove that `2 sin^2 (3pi)/4 + 2 cos^2 pi/4 + 2 sec^2 pi/3` = 10
If cos (α + β) = `4/5` and sin (α - β) = `5/13` where (α + β) and (α - β) are acute, then find tan 2α.
The value of cos(-480°) is:
