The expression is .
Consider .
Apply double angle formula : .
The exact value of .
.
The value of the expression is .
![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4107790a602f1f694d43af994d486b4c.png\")
..![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=709cb418667d655cc9c177809df06a45.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=16c29194323f2f5cc17fbe581ceae8ad.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=43bbd65a69fcfb9cc161f36d66a35afa.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=89e535d1d1d1007dfb77ec9759708374.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=9becc542c5cc92fe8cb6fec8132d90df.png\")
.![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=37135a9fd3c1dd35be6466b222ddd162.png\")
.