Advertisements
Advertisements
प्रश्न
Find the value of the following:
cosec 15º
Advertisements
उत्तर
cosec 15º = `1/(sin 15^circ)`
Consider sin 15° = sin(45° – 30°)
= sin 45° cos 30° – cos 45° sin 30°
`= 1/sqrt2 xx sqrt3/2 - 1/sqrt2 xx 1/2`
`= sqrt3/(2sqrt2) - 1/(2sqrt2)`
`= (sqrt3 - 1)/(2sqrt2)`
cosec 15° = `1/(sin 15^circ) = (2sqrt2)/(sqrt3 - 1)`
APPEARS IN
संबंधित प्रश्न
Find the value of the following:
sin (-105°)
Find the value of the following:
cos 70° cos 10° – sin 70° sin 10°
Find the value of the following:
cos2 15° – sin2 15°
If sin A = `3/5`, 0 < A < `pi/2` and cos B = `(-12)/13`, π < B < `(3pi)/2`, find the values of the following:
- cos(A + B)
- sin(A – B)
- tan(A – B)
If A + B = 45°, prove that (1 + tan A) (1 + tan B) = 2 and hence deduce the value of tan 22`1/2`.
If tan θ = 3 find tan 3θ
If tan A – tan B = x and cot B – cot A = y prove that cot(A – B) = `1/x + 1/y`.
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
The value of cos2 45° – sin2 45° is:
