Question

How do you find out when a number is rational

Answer 1

"Rational" means that you can express it as one integer divided by a number integer. If you can't find those two integers, then you can find a series of steps involving rational numbers to get to it, which will prove that the number is rational (because Q is a field).

Answer 2

can you give me aan example i have to pick between the sqaure roots of 18 24 36 and 38

Answer 3

i meant 48

Answer 4

Well, you can just compute those square roots:
\[\begin{align}
\sqrt{18}&=3\sqrt{2}\\
\sqrt{24}&=2\sqrt{6}\\
\sqrt{36}&=6\\
\sqrt{48}&=4\sqrt{3}
\end{align}\]
6 is rational (6/1), and all the others contain irreducible square roots, which are irrational, so they are too. Hence the answer is 36.

Answer 5

oh i get it ..it makes sense now.. when you gave me that definition it was to long