Write an equationthat is an identity.
An identity is an equation that is true for every value of the variable.
Therefore, is an identity since .
![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=aa8a6466828337f1bdaadb363c6c3604.png\")
is an identity since ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=cf6fbda6d76bcc27dbd12aa675678a09.png\")
.