Derivatives Quotes Derivatives?

Derivatives? - derivatives quotes

As derivatives are treated in mathematics? My sister is in equilibrium, and wanted to know Derivatives she was the course, but because the teacher is held by a disease or a species, it is not possible to teach the courses he / she derivatives. Your test is and has no knowledge at all?

So to summarize:

How do you explain derivatives in its simplest form?

I try to help, but only with adv. Math 11 does not help much.

Can someone help me here?

Note: Your teacher's words were: "The review has no boundaries, so it will not learn."