why $\sin^{-1}(x)+\cos^{-1}(x) = π/2$ How do i  find  the  When $x$ is  ranging from $-1$ to $1$?
I want know why $\sin^{-1}(x)+\cos^{-1}(x) = π/2$
I have already tried inverse-function.
thanks.

The "co" in "cosine" stands for "complement".  It means, the sine of the complementary angle.  Two angles are complementary if they add to a right angle, $\pi/2$ radians.  Thus:
$$
\arcsin x + \arccos x = \frac{\pi}{2}
$$
