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 101 What is the most expensive item I could buy with £50? 45 Has lack of mathematical rigour killed anybody before? 38 What's so special about characteristic 2? 21 What is a sharp constant? 19 Why not use two vectors to define a plane instead of a point and a normal vector?

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 +20 Difference between $\mathbb{Z}^2$ and $\mathbb{Z}\oplus \mathbb{Z}$ -2 Intuition on Strongly Stable Sets in a dynamical system +55 Is my proof of $f(A_1\cap A_2)\subset f(A_1)\cap f(A_2)$ correct? +10 Finding derivative of $|x|^p$ by the definition

### Questions (41)

 6 Show that in a complex Hilbert space, T normal bounded linear operator, $\| T^2 \| =\| T \| ^2$ 5 Prove that a group of order $p^2q$ has a proper normal subgroup. 5 Taylor series of ln(1/(1-z)) around 0 4 Degree of minimal polynomial for $\sin (\frac {2 \pi} 7)$ 3 Epimorphisms on category of (finite) bounded distributive lattices = surjective?

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 75 A strange integral: $\int_{-\infty}^{+\infty} {dx \over 1 + \left(x + \tan x\right)^2} = \pi.$ 24 Does a set $A \subseteq [0,1]$ exist such that $A$ is homeomorphic to $[0,1] \setminus A$? 4 I get two different answers on simple equation. What am I doing wrong? 4 Real matrix with the property that every nonzero vector in $\mathbb{R}^n$ is an eigenvector of $A$. [duplicate]

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