The expression is .
Rewrite the expression as .
Cancel common terms.
Apply special trigonometric limits .
.
![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=824704dfb934935530876625e06e9d52.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=3440617fd8499f80315d2e64c4ca389d.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=2f51cfa78cd8096e8c78c070c3d5873c.png\")
![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=1a5b889d2a3123106067c03f3cf4205b.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=346f89c32ec06cbd49e0ef8b566be67a.png\")
.![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=cdf44caced2460a82b9ce4d0e2ae519b.png\")
.