The trigonometric expression is .
Subtraction formula for trigonometric identity is .
Substitute and in the trigonometric formula.
The value of trignomoteric expression is .
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..![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=5859fe5c7aa9078ec5655fcaa59314c2.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=2afd80f8ed46df4f6294c46714c26567.png\")
and ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4c9e50c44c3cb474a090af43f45c46e2.png\")
in the trigonometric formula.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=3163bba229c9905ba6c87d58a41cca73.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=d19ea8dec317fbe5a411fa4b88fab0db.png\")
.