The expression is .
(Apply difference of angles formula: )
(The values of )
(Multiply)
(Simplify)
is an identity.
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=cafa56dd63bced9b9d6b7c75eefa696d.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=da5b597a7adf7229c32f2de3e0c22cf1.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=14f23f8cd4ec05ff916ee79cf444a66b.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=6f785d8bdfe5d5b49e3e2a4eafa70d51.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=2838fbff13757bd8335013d0d622a3b9.png\")
(The values of ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=7a9e742742f3a19ff18f7ed7048b7bf0.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=3a1afe898b482db6a7f611df6425f394.png\")
(Multiply)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b524ccaa47a3d2221d506a33ae76b479.png\")
(Simplify)![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
is an identity.