How could you check quickly the validation of an expression obtained by using the binomial theorem?

Answer 1

These pages will explain:

http://www.karlscalculus.org/l4_1.html

http://purplemath.com/modules/binomial.htm

This one has it's own calculator:
http://www.intmath.com/Series-binomial-theorem/4_Binomial-theorem.php

Is it from a textbook? If so, give me the name of the book, chapter and question number. I can probably find it for you.

Answer 2

Hmm... doubtful there is a quick check of your calculation, but maybe having a printout of Pascal's triangle in your notebook would reduce the work.