Question

If sin-1(x - x2/2 + x3/4 - ...) + cos-1(x2 - x4/2 + x6/4 - ....) = π/2, for 0 < |x| < √2, then x is

(a) 1/2

(b) 1

(c) - 1/2

(d) -1

Answer 1

Correct option (b) 1

Explanation:

(x - x2/2 + x3/4 - ...) = (x2 - x4/2 + x6/4 - ....)

Hence, the solution set is {0, 1}