Short proof:

Show that 1 and sqrt(2) are not commensurable.

I was given the definition "Two real numbers x and y are commensurable if there exists a real number u, and integers m and n so that m(u) = x and n(u) = y."

Question

Short proof:

Show that 1 and sqrt(2) are not commensurable. 

I was given the definition "Two real numbers x and y are commensurable if there exists a real number u, and integers m and n so that m(u) = x and n(u) = y."

anonymous · Answer

I should mention this is the 3rd question. The first was a proof that any two rational numbers are commensurable. 

The second was that if x, and a rational number a/b are commensurable, then x is a rational number. 

I wont write both of these out but they are quite short and I used their implications for my proof. So, unless otherwise requested I will considered them assumed true.

aravindg · Answer

Please post this in Mathematics group. That way there is more probability that your question will be answered.

anonymous · Answer

Arg, thought i was in math, my bad!

aravindg · Answer

np :) ...Close it and post it there!