The expression is .
(Rewrite )
(Apply difference 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=ddcdfa016cb2f6d69bb448273cd73f88.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4d8d59172885dc6382fab8c073fdb568.png\")
(Rewrite ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=aeaa298f9b95dedfd2cb9410f936cee8.png\")
)![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=14f23f8cd4ec05ff916ee79cf444a66b.png\")
) ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=6541d84faef7035453e8545a5abd1122.png\")
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step2.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=b6340980b007456a4371157352c43682.png\")
)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=fdd52329ae7121eed156d88e353d2945.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=3e42d9837c2bfa9a5fa2f930a5715b91.png\")
(Multiply)![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=eb11af52eafe7dc3c6edeaec48e4dc5e.png\")
(Simplify)![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=ee13175445330b12acc96e48cac71ee8.png\")
.