**Basic Trigonometric Identities**

1.

2.

3.

4.

**Pythagorean Identities**

1.

2.

3.

**Ex 1** Find if and is in
Quadrant II.

**Sol** , so since if is in Quadrant II. Then

.

**Ex 2** Find if and is in Quadrant III.

**Sol** Since , and and
therefore since for in Quadrant III.

**Pr A** Find if and .

**Pr B** Find if and .

**Pr C** Find if and .

**Pr 1** Find if and .

**Pr 2** Find if and .

**Pr 3** Find if and .

**Pr 4** Simplify the expression .

**Pr 5** Simplify the expression .

**Pr 6** Simplify the expression .

**Pr 7** Simplify the expression for with .

**Pr 8** Simplify the expression for with .

**Pr 9** Use trig identities to change to .

**Pr 10** Use trig identities to change to .

**Pr 11** Use trig identities to change to .

**Pr 12** Use trig identities to change to .

**Pr 13** Use trig identities to change to .

**Pr 14** Use trig identities to change to .

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