Q.

Let S  be the set of all solutions of the equation cos-1(2x)-2cos-1(1-x2)=π, x[-12,12]. Then xS2sin-1(x2-1) is equal to            [2023]

1 0  
2 -2π3  
3 π-2sin-1(34)  
4 π-sin-1(34)  

Ans.

(2)