Prove that if `xa n dy` are odd positive integers, then `x^2+y^2` is even but not divisible by 4.

Explanation

We know that any odd positive integer is of the form `2q+1 `for some integer q.


So, let `x=2m+1 and y=2n+1` for some integer `m` and `n.`




`\therefore x^2+y^2=(2m+1)^2+(2n+1)^2`


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