Legendre symbol

**joi** · May 15th 2011, 07:29 AM

Can't figure out why -(7/3)=-(4/3) Anyone can make it simple for me.

**tonio** · May 15th 2011, 07:42 AM

Originally Posted by joi

Can't figure out why -(7/3)=-(4/3) Anyone can make it simple for me.

$\binom{7}{3}=\binom{1}{3}=1\,,\,\,\binom{4}{3}= \binom{1}{3}=1$ , when taking $4,7=\!\!\pmod 3$

Tonio

**joi** · May 15th 2011, 09:08 AM

Thanks Tonio. Can somebody evaluate (7/79). I keep getting (-1). The answer in the back of the book is 1. Obviously I am making a mistake.

**AmateurStudent** · May 15th 2011, 10:39 AM

I get (7/79) = -(2/7) = -(1/7) = -1
Maybe the answer in the back of the book is wrong?

**Drexel28** · May 16th 2011, 07:55 PM

Originally Posted by AmateurStudent

I get (7/79) = -(2/7) = -(1/7) = -1
Maybe the answer in the back of the book is wrong?

Thread: Legendre symbol