The expression is .
(Rewrite )
(Apply sum of angles formula: )
(The values of )
(Multiply)
(Simplify)
The exact value of .
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=98f4f2d80e2b421f7dcfce5e67c1bf06.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=c800e085e274e69407e6ca4c16bd273d.png\")
(Rewrite ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=2439324d6289dc43d318f68522df5693.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b182d8e830db7ab827e97debe76a2c47.png\")
) ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=adac3e23cecae28b64ee75a9aef2cd11.png\")
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step2.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4109c80ac8404ff27b480216081cfa3c.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=e180b3c3be35e526a75e35fd0cd238b0.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=739189c37e41f2c37ba22997b210df25.png\")
(Multiply)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=aaf006de77c8a87f674b3bd84330b0b6.png\")
(Simplify)![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=9bea9d4a278142d37ca127f9974e6880.png\")
.