**Basic Trigonometric Identities**

**Sol A**
, so
since if is in Quadrant IV.

**Sol B**
, so
since if is in Quadrant III.

**Sol C**
, so
since if is in Quadrant IV.
Therefore
.

**Sol 1**
, so
since for
. Therefore
.

**Sol 2**
, so
since if
. Then
, so
.

**Sol 3** Since
,
and so
.
Therefore
since for
.

**Sol 4**
, which can also be written as
.

**Sol 5**
.

**Sol 6**
.

**Sol 7**
since
for
.

**Sol 8**
since
for
.

**Sol 9**
.

**Sol 10**
.

**Sol 11**

**Sol 12**
.

**Sol 13**
.

**Sol 14**

2004-04-21