Top network posts

• 51 Which $f$ satisfy the equation $\,\,f(x)\,f(y)-f(x+y)=\sin x\,\sin y\,$?
• 46 What is the remainder when $1! + 2! + 3! +\cdots+ 1000!$ is divided by $12$?
• 45 e is irrational
• 42 The equation $x^3 + y^3 = z^3$ has no integer solutions - A short proof
• 40 Is $\frac{\textrm{d}y}{\textrm{d}x}$ not a ratio?
• 39 Prove that $\int_0^1{\left\lfloor{1\over x}\right\rfloor}^{-1}\!dx={1\over2^2}+{1\over3^2}+{1\over4^2}+\cdots.$
• 39 If $\,\lim_{h\to 0}\frac{f(x+h)-f(x-h)}{2h}\,$ exists for every $x$, what does this imply for $f$?
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