When you calculate the partial derivative with respect to x, you treat y as a constant. Likewise when you differentiate with respect to y.
So you get:
You do the other one.
f(x,y)= arctan(y/x)
Im familiar with "outer" and "inner" derivates and usually know how to work them. I also know that the derivative of arctan = 1/(1+x^2)
so i get
f'x= 1/(1+x^2) * (y/x) * ??
What is the x-derivative of y/x ?
I also cannot seem to find the partial derivates to:
f(x,y)= (x+y)/(x-y)
Help would be highly appreciated...
Thank you both so much, this forum is amazing.
PS. If anybody else is eager to help Ive got another problem I can't solve
Determine x*(f'x)+y*(f'y)+z*(f'z)
if : f(x,y,z)= ln(x^3+y^3+^z^3 - 3xyz)
The answer is simply 3. But when I derivate with regards to x, y and z and put it into x*(f'x)+y*(f'y)+z*(f'z) I get something far more complicated which I cannot simplify.