If with then, taking squares . Now you can easily prove that would be a rational number (contradiction) .
P.S. There another way to prove it considering
Hi, I have this problem which I do not know how to solve... thanks for any help you can give me! And please, if you can solve it, I would really appreciate it if you could tell me the theorem you have used since I am feeling so lost in abstract algebra
"Let be the set consisting of all numbers of the form
where a and b belong to (the set of all rational numbers). Prove that does not belong to ."