What does this notation mean in mathematics?

Question

Mathematics

I know that the derivative in mathematics is displayed as y' But what does this display mean? d*x / d*y

Answer 1

Partial derivative

Answer 2

The derivative function shows the rate of change of this function, respectively, to find out the rate, it is necessary to calculate by how many units one parameter has changed in relation to the other. This d, that is, the differential, is, in a simpler sense, a change