What is geometrical representation of partial derivatives?
The partial derivative of z=f(x,y) have a simple geometrical representation. Suppose the graph of z = f (x y) is the surface shown. Consider the partial derivative of f with respect to x at a point. Holding y constant and varying x, we trace out a curve that is the intersection of the surface with the vertical plane. The partial derivative measures the change in z per unit increase in x along this curve. Thus, it is just the slope of the curve at a value of x. The geometrical interpretation of is analogous in both types of derivatives, i.e., Ordinary and Partial Derivatives