The expression is .
Generally can write sigma rotation as .
Consider .
Rewrite the expression in sigma notation and simplify.
The value of the expression is
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=f4adebce547ff349c7f4d8aa4fe09db6.png\")
..![\"image\"](\"http://www.mathskey.com/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=685a6f257a27276b7697209b33d043a0.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=4f261d7d90256082233466d81f6c5e81.png\")
.![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=84f18363b2cb993f9eea0786b90b05b9.png\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=45012535e48d4b86cab65e61c4b46bbf.png\")