The first page of http://www.math.ca/crux/v31/n8/public_page502-503.pdf contains the expansion of . Similarly expand and add them.
The question:
Show that , for all complex numbers and .
I tried getting the LHS to match the RHS, but I've done something wrong. My attempt involved factorising using the difference of two squares, but it doesn't seem to help. Any assistance would be great.
The first page of http://www.math.ca/crux/v31/n8/public_page502-503.pdf contains the expansion of . Similarly expand and add them.