Top network posts

• 33 using numbers 1 to 9 only once to equal 1 million
• 26 Prove that $\mathbb{R^*}$, the set of all real numbers except $0$, is not a cyclic group
• 19 Series with factorial.
• 18 Prove that $g(x)=\frac{\ln(S_n (x))}{\ln(S_{n-1}(x))}$ is increasing in $x$, where $S_{n}(x)=\sum_{m=0}^{n}\frac{x^m}{m!}$
• 18 Let $f \in \Bbb Z[x]$ such that there exist distinct $a$, $b$, $c$ and $f(a)=f(b)=f(c)=1$. Prove that there is no $d \in \Bbb Z$ such that $f(d)=0$
• 16 Polynomial always non-negative
• 13 problem proving: $(1+q)(1+q^2)(1+q^4)...(1+q^{{2}^{n}}) = \frac{1-q^{{2}^{n+1}}}{1-q}$
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