Hi, I have an exam tomorrow and I'm trying to do the following question which I've almost solved:
Find the perfect differential of the following:
[(x² + 2xy) / (x + y)² ]dx - [x² / (x + y)² ]dy
I differentiated the first term with respect to 'y' and then the second term with respect to x, equated them but they werent the same, what could I be doing wrong?
The problem is I can't seem to get both terms to equal eachother unless i cancel the denominator..but why cant i get them to equal eachother if i differentiate with the denominators too? Should be the same...?