SOLUTION: Show that if x^2 is odd, x is odd. Use proof by contradiction.

Algebra.Com
Question 992554: Show that if x^2 is odd, x is odd. Use proof by contradiction.
Answer by ikleyn(52803)   (Show Source): You can put this solution on YOUR website!
.
Show that if x^2 is odd, x is odd. Use proof by contradiction.
----------------------------------------------------------------

We are given that    is odd.
We need to prove that  x  is odd.

Let us assume that  x  is not odd.  Then  x  is even.  In other words,  x  is divisible by  2.  Hence,  x = 2n,  where  n  is integer.

Then   = =  is even.

This contradicts to the fact that    is odd,  which is given.

The source of the contradiction is the assumption that  x  is not odd.

Hence,  x  is odd.

The proof is completed.


RELATED QUESTIONS

proof by contradiction if 3n+1 is odd then n is also... (answered by fcabanski)
Prove that the product of two odd numbers is odd, using an indirect proof and a proof by... (answered by josgarithmetic,ikleyn)
Using proof by contradiction, show that (3+√2)/3 is... (answered by math_helper)
Using proof by contradiction, prove that 7√2 is... (answered by MathLover1)
Use proof by contradiction to prove/disprove that no integers x and y exist such that... (answered by ikleyn)
show that if f is any function thaen the function 0 defined by 0(x)=f(x)-f(-x)/2 is... (answered by robertb)
x and y are integers. show that x^2-y^2 is odd or divisible by... (answered by Jk22)
The section that I am on in my class is over contradiction. The equation is Show that... (answered by mbarugel)
If c is asn odd integer, the show that the equation x^2+x-c=0 has no integer... (answered by Fermat)