" If u be a homogeneous function of degree n,then "x(del^(2)u)/(del x^(2))+y(del^(2)u)/(del y^(2))=

If u is a homogenous function of x and y of degree n, then x(del^(2)u)/(del x^(2)) + y(del^(2)u)/(del x del y) = __________ (del u)/(del x) .

If f (x,y) is homogeneous function of degree 5 then x (del f)/(delx) +y (del f)/( del y)=

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

A function f (x,y) is said to be harmonic if (del^(2)f)/(del x ^(2)) + (del^(2)f)/(dely^(2)) =

If u= x^3-3xy^2 , show that (del^2u)/(delx^2)+(del^2u)/(dely^2) =0

If V(x,y) = e^(x) (x cos y - y siny) , then prove that (del^(2)V)/(del x^(2)) + (del^(2) V)/(del y^(2)) =0

If u=f(y/x) , then x(del u)/(del x) + y(del u)/(del y) =_________

If z=f(x-cy) + F(x+cy) where f and F are any two functions and c is a constant, show that c^(2) (del^(2)z)/(del x^(2)) = (del^(2)z)/(del y^(2)) .

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

If u=x^y then find (del u)/(del x) and (del u)/(del y) .