The domain of the function f(x) = sin-1(|x| + 5x2 + 1) is (-∞, -a] ∪ [a, ∞). Then the value of a is equal to:

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.