The trigonometric equation is .
Left side of the equation = .
Apply product of sum and difference formula: .
.
Pythagorean identity:
= Right side of the equation.
Therefore, .
![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5ec3e62cda690192e4b573f784a96a1a.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=43cad434634d6e3e854dd2c9288c9dcc.png\")
.![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=51a3819c48c593a0a77e70a9a07daf61.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=992db8ea52b27fd4a698b82d95573d89.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=12a65b257ec9da63167201bf2258308f.png\")
.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step2.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=c861b17a44efaf1c09427eed96b5feab.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=68b8da15bf483f4b28efe8271a8f7c01.png\")
![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5ec3e62cda690192e4b573f784a96a1a.png\")
.