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Using the words necessary and sufficient rewrite the statement The integer `n` is odd if and only if `n^2` is odd Also check whether the statement is true.

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Let P: The interger n is odd. And `q:n^2 `is odd.
First n be odd: Then,
`n=(2k+1)` for some interger K.
Then `n^2(2k+1)^2=(4k^2+4k+1)=2(2k^2+2k)+1 `
This n^2 is 1 more than an even number and therefore ,it is odd.
Thus `p⇒q`
Now ,in order to prove that `q⇒p` it is sufficient to show
that `~p⇒q`[Contrapositive method ]
Clearly `~ P` The interge n is even
...
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