Prove sq root of 2 + sq root of 3 is irrational

1. Apr 7, 2009

yanjt

hi,i read the post of sq root of 2 + sq root of 3.i understand tat i should use contradiction to solve it.yet,i stuck halfway when i tried to solve it.
sq root 2 + sq root 3 = p/q
2 + 2*sq root 6 +3=p^2/q^2
5+2*sq root 6 = p^2/q^2
wat should i do after this?i hav to prove that the addition of a raitonal and irrational number is irrational?

2. Apr 7, 2009

matt grime

Rearrange, and you see that you have to show that sqrt(6) is rational: rational plus rational is rational

See above.