If `sin alpha=15/17, pi/2 < alpha < pi ` and `cos beta = -4/5, pi < beta < (3pi)/2 ` find `cos (alpha-beta) `

If pi/2 lt alpha lt pi, pi lt beta lt 3pi/2; sin alpha = 15/17 and tan beta = 12/5 , then the value of sin(beta - alpha) is (A) -171/221 (B) -21/221 (C) 21/221 (D) 171/221

If sin theta=15/17 and theta lies in 1st quadrant, then cos theta=?

If sin alpha = (-3)/(5), where pi lt alpha lt (3pi)/(2), then cos ((alpha)/(2))= ................ A) (-1)/( sqrt10) B) (1)/(sqrt10) C) (3)/(sqrt10) D) (-3)/(sqrt10)

If 10sin^4 alpha+15 cos^4 alpha=6, then find the value of 27 cosec^6 alpha+8sec^6 alpha. .......... A) 125 B) 250 C) 50 D) 75

If sin (alpha - beta) =1/2 and cos (alpha + beta) =1/2, where alpha and beta are positive acute angles, then alpha and beta are

If (2sin alpha)/({1+cos alpha + sin alpha})=y, then ({1-cos alpha+sin alpha})/(1+sin alpha)=

If sinalpha=(-3)/5 , where pi<(alpha)<(3pi)/2 , then cos(alpha/2)=

The value of expression (1+ sin 2 alpha)/(cos (2 alpha -2pi) tan (alpha -(3pi)/(4)))- 1/4 sin 2 alpha (cot ""(alpha)/(2) + cot ((3pi)/(2)+(alpha)/(2))) is

Let alpha, beta be such that it pi < alpha - beta <3 pi . if sin alpha + sin beta =-21/65 and cos alpha+cos beta = -27 / 65 then the value of cos ((alpha-beta)/2) is