The trigonometric function is .
The reciprocal identity of .
Observe the unit circle.
.
The value of .
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=778416ace02143f60d991a6d2ba319b2.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=9c21aff5746f03ac3d38f3859bcd3c81.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=3881df6fac2ba1560ffbf5e3a9c11ddd.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5b3768c839bdc66bd9887ff680f204e6.png\")
.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=f23f807377e6f18346cbbf8cb547cf44.png\")
.