Tuesday, January 29, 2008

binomial factors

(2^2 - 1)( 2^2 + 1)( 2^4 + 1)(2^8 + 1)

A. 2^16 - 1
B. 2^16 + 1
C. 2^32 - 1
D. 2^128 - 1
E. 2^16.(2^16 - 1)

1 comment:

Luís Botelho Ribeiro said...

If you bear in mind that known property stating that (a-b)(a+b)=(a^2-b^2) you realise that the first two factors correspond to:
(2^4 - 1).

Then, we now have only 3 factors:
(2^4 - 1).(2^4 + 1).(2^8 + 1)

Repeating the observation, the first two factors simplify to:
(2^8 - 1) x (2^8 + 1)

By the same property, we finally get:
(2^16 - 1)

:. Option A. is correct.





is result is actually similar th