### Questions (72)

 13 If $A+B=AB$ then $AB=BA$ 8 Show that the polynomial $p_0, p_1, \ldots, p_m$ are linearly dependent. 6 How to determine the $\lim_{n\to \infty} \frac{1+2^2+\ldots+n^n}{n^n}=1$. [duplicate] 4 The set of points of discontinuity is precisely an open set $U\subset \mathbb{R}^n$ 4 Dimension of $U+V$

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 6 On the proof $\tan 70°-\tan 20° -2 \tan 40°=4\tan 10°$ 6 Variation on Pythagoras: If $a^2 + b^2 = c^2$, then $a + b \leq c\sqrt{2}$ 5 I'm not sure I'm correct: $\|\sum_{n=1}^\infty x_n\| \leq \sum_{n=1}^\infty \|x_n\|$ 4 Evaluating $\int_0^1 \binom{n}{y} x^y(1-x)^{n-y}dx$. 4 Show unit circle under multiplication not isomorphic to either the nonzero real numbers under multiplication or real numbers under addition

### Tags (113)

 18 abstract-algebra × 11 8 integration × 6 16 calculus × 9 8 ring-theory × 4 13 inequality × 3 7 normed-spaces × 4 13 trigonometry × 3 7 norm × 2 8 functional-analysis × 8 6 real-analysis × 20

### Bookmarks (7)

 30 Perfect set without rationals [closed] 23 Normal subgroups of $S_4$ 3 Triangle inequality for Minkowski functional 2 Absolute convergence does not implies convergence 2 Hahn Banach extension of the following functional.

### Accounts (12)

 Mathematics 2,357 rep 99 silver badges2525 bronze badges TeX - LaTeX 173 rep 77 bronze badges History of Science and Mathematics 101 rep Stack Apps 101 rep MathOverflow 101 rep 11 bronze badge