#### carabrown

Hi (Nod)

I was wondering if anyone could help me on this problem I am having.

I have the equation:

y^2 = 2( x^4 -17)
(which I am showing has no real solutions but has solutions in the p-adic numbers i.e. a counterexample to the hasse principle)

I need to show that it has a non trivial solution in R and in Q_p (p-adic numbers for p=2, 17 (the 2-adics and 17-adic)

Any help or advice would be so much apprciated! Im completely stumped!

THANKS!!

Cara

xxxx

Last edited by a moderator:

#### chiph588@

MHF Hall of Honor
What do you mean by no trivial solution in $$\displaystyle \mathbb{R}$$?

In $$\displaystyle \mathbb{R}$$ we have solutions $$\displaystyle \left(x,\pm\sqrt{2(x^4-17)}\right)$$ for all $$\displaystyle |x|>\sqrt{17}$$.

#### carabrown

Sorry that was a typo! Thats meant to be in Q.
this equation has nontrivial solutions over​
Qp for all prime numbers p and over R but has no nontrivial solutions over Q.
I need to show that although there is no solution in Q there is a solution in Qp . But I dont know how to show that for the case where modulo p=2 and modilo p=17?

Its a special case, but its completely confused me.
Thanks so much for the reply!