Solwant to solve a 2nd ving a partial differential equation with textbook solution

[Anthony The Koala]

First I managed to solve a 2nd order ode using the symbolic letters as in:
desolve(∂(∂u/∂x)∂x+3*∂u/∂x=0,x,y)

Now want to solve a 2nd order partial differential equation, pde

My Reference for a textbook solution is from the book "Advanced Mathematics For Engineering Students", page 131.

In the textbook
The 2nd order pde is
∂2u/(∂x∂y) = 2x - y.

The general solution is:

u = x^2*y - 1/2*x*y^2 + F(x) + G(y)

Where:
F(x) = 2* sin(x) and
G(y) = 3*y^4- 5

Entering the pde in the Prime [/b][/align]n CAS mode:

b]desolve(∂(∂u/∂y)∂x+y-2*x=0,x,y,u)[/b]

The answer is
[1/2*y]

It was not the textbook's answer.

Question: why didn't the output from the prime match the textbook answer?[b]

Thank you,
Anthony, Sydney