Friday, 1 August 2014

elementary number theory - Prove that if (n1)!equiv1modn then n is prime.

Let n be a natural number, n2. Prove that if (n-1)!\equiv-1 \mod n then n is prime. I tried few things but I my skills in equations modulo n are not well enough. I would really appreciate your help.

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real analysis - How to find lim_{hrightarrow 0}frac{sin(ha)}{h}

How to find \lim_{h\rightarrow 0}\frac{\sin(ha)}{h} without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...