If `iz^(4) +1= 0`, then prove that z can take the values `cos pi//8+ i sin pi//8`

Find the value of tan (pi/8)

Evaluate cos^2(pi/8)+cos^2((3pi)/8)

Find the value of sin^-1(sin((3pi)/4))

The value of cos (pi// 4 + x) + cos (pi// 4 - x) is

The value of [ cos ""(pi)/(8) + isin ""(pi)/(8) ]^(4) is

The expression sin^(-1)(1-x)+cos^(-1)sqrt(x-2) can take the value A)0 B) pi//2 C) -pi//2 D) pi

The function f(x) = sin^(4)x + cos^(4) x increases if a) 0 lt x lt pi//8 b) pi//4 lt x lt 3 pi//8 c) 3 pi//8 lt x lt 5pi//8 d) 5 pi//8 lt x lt 3 pi//4

If iz^(3)+z^(2)-z+i=0 , where i= sqrt-1 then |z| is equal to

If 8 cos 2 theta + 8 sec 2 theta = 65, 0 lt theta lt (pi)/(2) , then the value of 4 cos 4 theta is equal to a) (-23)/(8) b) (-31)/(8) c) (-31)/(32) d) (-33)/(32)

The value of int_(0)^(pi//2)sqrt((sin2theta))sinthetad theta is a) pi//2 b) pi//4 c) pi//8 d) pi//16