Is this a complete proof
Suppose a is an integer.
Claim. a^3+a^2 is even.
“Proof.” a^3+a^2 = a^2(a+1), which is always an odd number times an even number. Therefore, a^3 + a^2 is even.

Question

Is this a complete proof
Suppose a is an integer.
Claim. a^3+a^2 is even.
“Proof.” a^3+a^2 = a^2(a+1), which is always an odd number times an even number.  Therefore, a^3 + a^2 is even.

shubhamsrg · Answer

yep,,i'd say a good proof..

swissgirl · Answer

hmmm i am just wondering if its missing any steps

shubhamsrg · Answer

well if you want to add something you may mention a^2 is odd is a is odd which makes a+1 even
and vice versa when a is even
otherwise its a fine enough proof..

anonymous · Answer

2 cases a is even or a is odd, then continue for each case....

swissgirl · Answer

that is what i was thinking