" If "u=x^(2)tan^(-1)(y)/(x)-y^(2)tan^(-1)(x)/(y)" then "(del^(2)u)/(del x del y)=

If u = x ^ (2) tan ^ (- 1) ((y) / (x)) - y ^ (2) tan ^ (- 1) ((x) / (y)), prove that (del ^ (2) u) / (del x del y) = (x ^ (2) -y ^ (2)) / (x ^ (2) + y ^ (2))

If u (x,y) = (x ^(2))/( y)- (2y ^(2))/(x) then (del^(2) u)/(del x dely) - (del ^(2) u)/(dely delx) is :

If u= y sin x then (del^(2)u)/(del x del y) =___________

If f(x,y) =e^(xy) , then (del^(2)f)/(del x del y) is equal to

If u =tan^(-1)((x)/(y)) show that (del^(2)u)/(delxdely) = (del^(2)u)/(delydelx) .

If f (x,y) =e ^(xy) then (del^(2)f)/(delx dely) at (1,1) is:

If u= tan^(-1) ((x^(3) + y^(3))/(x-y)) , Prove that x(del u)/(del x) + y(del u)/(del y) = sin 2u .

If u=ax-by , then ((del u)/(del y))=

If u=(x-y)^(2) , then (del u)/(del x) + (del u)/(del y) is