Find the principal value of sin^-1\(\left( -\frac { 1 }{ 2 } \right) \)(in radians and degrees).

Find the principal value of sin^-1(2), if it exists.

Find the principal value of
 \({ Sin }^{ -1 }\left( \frac { 1 }{ \sqrt { 2 } } \right) \)

Find all the values of x such that -10\(\pi\)\(\le x\le\)10\(\pi\) and sin x = 0 

Find the period and amplitude of y = sin 7x