Failed to connect to MySQL: Access denied for user 'examnext_online'@'localhost' (using password: YES) If `x in [-1, 0)` then `cos^-1 (2x^2-1)-2 sin^-1 x=` - Sarthaks eConnect

If `x in [-1, 0)` then `cos^-1 (2x^2-1)-2 sin^-1 x=`

`–pi/2`

`pi`

`(3pi)/2`

`-2pi`