Discrete Math 1.7.3 Proof by Contradiction

[madigodinez]

For the second example, why did you assume n was odd? If n being even was the ‘q’, I thought we were assuming ‘not p’ instead of ‘not q, ’ which is what you did.

[benhaenraets]

For the second example... Would it still be considered correct if I used this working...

assume n is odd such that n = 2c + 1 where c is any integer. So 3n+2 = 6c+5 and is even. We know even = odd + odd, so 6c must be odd, which is a contradiction...

A reply would be much appreciated!

[cshivani]

For 3n+2 case of proof you could use contrapositive or contradiction, both look similar as in you assumed n is not what is expected so assumption is getting violated. My question is how to know which type of proof to apply for a case and what are differences between the above 2 ways . Thanks, appreciate your teaching very much !!

[miriamDev]

Hi Kim, how do you solve a proof problem with log format.

[Tnt-ywqt]

Hi what software diid you use ? did you use surface pro ?

[fashionvella]

can you please tell me why a must be even

[hirakumurakami]

3n+2 is even then n is even
assume n is odd
n=2n-1
3(2n-1)=-2
6n-3=-2
6n=1
This is false, therefore by proof of contradiction, n has to be even


wouldnt this work better and is simpler?