Question

how do you find sin^-1 (sin (4pi)/(7)) ?

Answer 1

answer is zero

Answer 2

Taking the sin^-1 of a value gives you the angle for which the sin of that angle is the value you took the sin^-1 of. For example, if the sin of x is y, then the sin^-1 of y is x. By that logic, the sin^-1 of the sin of a number is that number, so sin^-1 (sin (4pi)/(7)) is (4pi)/(7).