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In this video we introduce the Sum and Difference trigonometric formulas. For example, the
formula for the sine of alpha plus beta. There are situations where these formulas are useful.
For example, if we need to calculate the sine of seventy five degrees, we can view it as the
sine of thirty plus forty five, and we can do it without a calculator, using the so-called special triangles.

In this video we go over all those formulas and do a couple of examples to show you how to use them.