AB=(1/4)((A+B)2-(A-B)2) is an amazing identity, and...
AB=(1/4)((A+B)2-(A-B)2) is an amazing identity, and unfortunately I have to remind my current students how to prove it.
AB=(1/4)((A+B)2-(A-B)2) is an amazing identity, and unfortunately I have to remind my current students how to prove it.