If `alpha =pi/13` then the value of `prod_(r=1)^6cosralpha` is equal to

If alpha=pi/(15),\ then the value of prod_(r=1)^7cos ralpha is- a. 1/(128) b. 1/(128) c. 1/(64) d. 1/(32)

The value of prod_(r=1)^(7)cos\ (pi r)/(15) is

The value of prod_(r=1)^(7)cos\ (pi r)/(15) is

let z_1,z_2,z_3 and z_4 be the roots of the equation z^4 + z^3 +2=0 , then the value of prod_(r=1)^(4) (2z_r+1) is equal to :

let z_1,z_2,z_3 and z_4 be the roots of the equation z^4 + z^3 +2=0 , then the value of prod_(r=1)^(4) (2z_r+1) is equal to :

If underset(r=1)overset(10)sum r! (r^(3)+6r^(2)+2r+5)=alpha (11!) , then the value of alpha is equal to .......

If alpha in [pi/2,pi] , then the value of sqrt(1+sin alpha)- sqrt(1-sinalpha) is equal to:

If alpha in [(pi)/(2),pi] then the value of sqrt(1+ sin alpha)-sqrt(1 - sin alpha) is equal to

If alpha in(-(3 pi)/(2),-pi), then the value of tan^(-1)(cot alpha)-cot^(-1)(tan alpha)+sin^(-1)(sin alpha)+cos^(-1)(cot alpha) is equal to (a)2 pi+alpha(b)pi+alpha(c)0(d)pi-alpha