If α = π4 + ∑p=111 tan-12p-11 + 22p-1, then the value of tan(α) is:

The value of cos(sin-1(513)) is equal to:

The solution of the equation 3 tan-1(x) - 2 cot-1(x) = π2 in the first quadrant is ________.

If sin-1(1 - x) - 2sin-1(x) = π2, then find the value of x.