**Trigonometry: Addition Formulas**

The addition formulas for the sine and cosine are given by

The addition formulas for the tangent are given by

**Ex 1** Find using an addition formula.

**Sol**
.

**Ex 2** Find using an addition formula.

**Sol**
.

**Pr 1** Find using an addition formula.

**Pr 2** Find using an addition formula.

**Pr 3** Find
using an addition formula.

**Pr 4** Use an addition formula to simplify
.

**Pr 5** Use an addition formula to simplify
.

**Pr 6** Find using an addition formula.

**Pr 7** Use the addition formulas to simplify the expression

**Pr 8** Find the smallest positive angle between the lines with
equations and .

Go to Solutions.

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Lawrence Marx 2002-07-11