The inverse of a function f:A→B exists if f is one-one onto i.e.,
y=f( x )⇒ f −1 ( y )=x .
The given inverse trigonometry function is cos −1 ( 1 2 )+2 sin −1 ( 1 2 ) .
Let,
cos −1 ( 1 2 )=x cosx= 1 2 =cos( π 3 )
Therefore, cos −1 ( 1 2 )= π 3
Let,
sin −1 ( 1 2 )=y
siny= 1 2 =sin( π 6 )
Therefore, sin −1 ( 1 2 )= π 6
According to the question, summation of all the functions gives,
cos −1 ( 1 2 )+2 sin −1 ( 1 2 ) = π 3 + 2π 6 = π+π 3 = 2π 3
Thus, the value of cos −1 ( 1 2 )+2 sin −1 ( 1 2 ) is 2π 3 .