# Tagged Questions

Use the convention tag for questions about standard, cultural practices in mathematics.

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### Why does this text insist on changing the variable name here?

In What is mathematics? by Courant, Robbins, and Stewart, "5. An important inequality", the authors change $n$ in this example: $$(1+p)^n\geq1+np$$ to $r$ in this example: $$(1+p)^r\geq1+rp$$ In ...
Consider the sequence $S = (A, B, C, D, E)$ and the permutation $\pi = (4, 1, 3, 5, 2)$: Which of the following is true? $$\pi(S) = (B, E, C, A, D) \quad and \quad \pi^{-1}(S) = (D, A, C, E, B) \... 1answer 178 views ### Prove thoroughly: If the degree of all vertices is greater or equal to \frac{|V| - 1}{2}, then the simple graph is connected. I am struggling to write a good, thorough proof. The proof is supposed to be logically rigorous, correct and complete (e.g. no hidden assumption). Moreover, style is important - the proof should be ... 1answer 169 views ### Difference of 2 notations with powerset Let \mathbb{N}, \mathbb{V} two sets, \mathcal{P}(\ldots) means the power set of a set. \mathcal{P}({\mathbb{N}})\rightarrow \mathbb{V} can be the type of a function mapping a part of \mathbb{N}... 1answer 137 views ### How to translate math technical terms? What is a good way to translate mathematical technical terms? This can sometimes be hard because some words have different meanings in some language. For example: "eigenwert" (= "eigenvalue" in ... 1answer 305 views ### Normalization of Orthogonal Polynomials? The generalized Rodrigues formula (Hassani, Mathematical Physics, p. 174) is of the form$$p_n=K_n\frac{1}{w}\left(\frac{d}{dx}\right)^n(wp^n) The constant $K_n$ is seemingly chosen completely ...
Why is the principal square root of a complex number defined as $\sqrt z = \sqrt r e^{-i \varphi / 2}$ for $\varphi \in (-\pi, \pi]$ ? Wouldn't it be more natural to let $\varphi \in [0, 2\pi)$ as it ...