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Jean-Claude Arbaut's user avatar
Jean-Claude Arbaut's user avatar
Jean-Claude Arbaut's user avatar
Jean-Claude Arbaut
  • Member for 11 years, 6 months
  • Last seen this week
  • Besançon, France
70 votes
Accepted

Why are the trig functions versine, haversine, exsecant, etc, rarely used in modern mathematics?

43 votes

In plain language, what's the significance of a field?

39 votes
Accepted

How to prove Fibonacci sequence with matrices?

27 votes

How can you derive $\sin(x) = \sin(x+2\pi)$ from the Taylor series for $\sin(x)$?

26 votes

Which polynomials fix the unit circle?

25 votes
Accepted

Process to show that $\sqrt 2+\sqrt[3] 3$ is irrational

23 votes

How to prove that $f(f(x))=-x$ implies that $f$ is not continuous?

22 votes
Accepted

What are primitive roots modulo n?

21 votes
Accepted

Value of $f'(0)$ if $f(x)=\frac{x}{1+\frac{x}{1+\frac{x}{1+\ddots}}}$

18 votes

Estimating the value of $e$ using a random function

16 votes

Can $\sqrt{n} + \sqrt{m}$ be rational if neither $n,m$ are perfect squares?

15 votes

Determine whether $\sqrt{\sqrt{5}+3}+\sqrt{\sqrt{5}-2}$ is rational

15 votes
Accepted

How do you build a square from this figure?

14 votes
Accepted

Show that $\left\vert\frac{\pi}{4} - \left(1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \frac{1}{9}\right)\right\vert < 0.1$

13 votes

Having hard time understanding proofs by contradiction.

13 votes

Calculate more digits of square root of 2?

13 votes

Find the tenth derivative of $x^2e^x$

12 votes

Approximating Logs and Antilogs by hand

12 votes
Accepted

How to arrange functions in increasing order of growth rate , providing f(n)=O(g(n))

12 votes
Accepted

Properties of a continuous map $f : \mathbb{R}^2\rightarrow \mathbb{R}$ with only finitely many zeroes

12 votes
Accepted

Integration of $x^3 e^x$

12 votes

Find an increasing sequence of rationals that converges to $\pi$

12 votes

Find $\int_0^{2\pi}\frac1{5-4\cos x}\ dx$

12 votes
Accepted

Prove $x^3 + x +1 = 0$ has no rational solutions.

11 votes
Accepted

Is there any trilateral figure in euclidean geometry that is not a triangle?

11 votes

Geometry of the set of coefficients such that monic polynomials have roots within unit disk

11 votes
Accepted

Is there any methods to solve for integer solution of a quadratic equation like $ax^2 + bx + c = 0$

11 votes
Accepted

How many prime numbers are there in between $1000!+1$ and $1000!+1000$, inclusive?

10 votes

$1/i=i$. I must be wrong but why?

10 votes
Accepted

What is $\frac{d(\arctan(x))}{dx}$?

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