Different between Partial and Ordinary derivative

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I took already Calculus and Ordinary differential equations but my fluids mechanics Professor ask us to write to pages about the difference between a partial and a ordinary derivative. The problem is that the only thing I know is that ordinary derivative are the differentiation of a function of one variable, and partial derivative the differentiation of a function of multiple variables about one variable.

This won't fill 2 pages. Somebody could help with some other differences?

 

[EnumaElish]

Comparing the total (ordinary) derivative of a function with multiple variables to the partial der. with resp. to one of the variables would be more illuminating and voluminous.