If ` u = x^(2) + y^(2) " and " x = s + 3t, y = 2s - t , "  then " (d^(2) u)/(ds^(2))` is  equal to
Channel: Doubtnut
Date: 17/05/2020

If ` u = x^(2) + y^(2) " and " x = s + 3t, y = 2s - t , "  then " (d^(2) u)/(ds^(2))` is  equal to