Posted by Anonymous on Sunday, August 11, 2013 at 7:54am.
If m and n are integers such that mn is even, then m is even or n is even.
how can i prove this using contraposition?

DISCRETE MATHS  Steve, Sunday, August 11, 2013 at 6:07pm
if both are odd, we can let
m = 2a+1
n = 2b+1
mn = (2a+1)(2b+1) = 4ab+2a+2b+1
so, mn is odd if m and n are both odd.
So, if mn is even, then m and n cannot both be odd.
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