What these signs are telling?

[Guest]

Hello,

I wonder what these mathematical signs and notations are telling in this equation given in the photo here. How can I learn about these operations and their purpose? Thanks.

[shyamjayakannan]

these are called partial derivatives. For example here, [tex]u[/tex] may be a function of both [tex]x[/tex] and [tex]y[/tex], but [tex]\frac{\partial u}{\partial y}[/tex] means you need to take the derivative only with respect to [tex]y[/tex] and should tread all other variables as constants.

Ex: Suppose [tex]u(x,y)=x^2y^2[/tex], then [tex]\frac{\partial u}{\partial y}=2x^2y[/tex]