If `(sin^-1x+sin^-1w)(sin^-1y+sin^-1z)=pi^2`, then

Explanation

given `pi^2 = pi xx pi = - pi xx - pi`

`(sin^-1 x + sin^-1 w)(sin^-1 y + sin^-1 z) = pi xx pi `

max value of `sin^-1 x + sin^-1 w = sin^-1 1 + sin^-1 1 = pi/2 + pi/2 = pi`

max `(sin^-1 y + sin^-1z) = -pi/2 - pi/2 = -pi`

`pi^2, x=1, w=1, y=1, z=1`

`D= |(1,1),(1,1)| = 0`

when `-pi^2 , x=y=z=w=-1`

`D= |(-1^(n1), -1^(n2)), (-1^(n3), -1^(n4))|`

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