I have a question about Legendre symbol or I think that we will use Legendre symbol I am not sure,because I tried to apply the definition of Legendre symbol, quadratic reciprocity and also the properties of Legendre symbol but I could not succeed... Perhaps that question needs something else than Legenndre symbol.

Here is the question:

"Calculate (3/10) and also calculate (2/15)"

Thanks for your help...


This is not the Legendre symbol, but the Kronnecker symbol, and we have $$ \left( \frac{3}{10}\right)=\left( \frac{3}{2}\right)\left( \frac{3}{5}\right)=-1\cdot (-1)=1. $$ Do the same with $\left( \frac{2}{15}\right)$.

  • $\begingroup$ thanks dietrich burde.i did not think jacobi. $\endgroup$ – juliet Nov 14 '13 at 9:37
  • $\begingroup$ Here $(3/2)=-1$ is the Kronnecker symbol $(a/2)$. The Legendre symbol $(a/p)$ is for primes $p\neq 2$. $\endgroup$ – Dietrich Burde Nov 14 '13 at 10:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.