Skip to main content
alans's user avatar
alans's user avatar
alans's user avatar
alans
  • Member for 10 years, 11 months
  • Last seen this week
  • Serbia, Belgrade
34 votes
Accepted

Finding the roots $x^4-4x^3-x^2-8x+4=0$ (contest math)

15 votes

How to prove a function is always continuous?

13 votes
Accepted

Integral $\int \sqrt{1+x^2}dx$

13 votes
Accepted

Prove that there exists $c\in\mathbb{R}$ such that $f'(c)=f(c)$

13 votes
Accepted

How to find a minimal polynomial (field theory)

12 votes

Linear independence of functions: $x_1(t) = 3$, $x_2(t)=3\sin^2t$, $x_3(t)=4\cos^2t$

11 votes

How can I evaluate $\lim_{x \rightarrow 0} \frac{\left(\sqrt{2+x}-\sqrt{2} \right)}{ x}$?

11 votes
Accepted

(Tournament of towns 1994) Prove the inequality

9 votes

If $(w + 1)(w - 1) = w$, find $ { w }^{ 10 }+\frac { 1 }{ { w }^{ 10 } } $.

9 votes
Accepted

Problem with counting limit.

9 votes
Accepted

Prove that two sets are the same

8 votes
Accepted

Why is my solution of $e^{\sin x } - e^{- \sin x} - 4 = 0$ wrong?

8 votes
Accepted

Simplifying logarithms and changing base

7 votes

$f(0)=f(1)$ but no point with $f'(0)=0$?

7 votes

Is every odd order skew-symmetric matrix singular?

6 votes

Finding integrating factor for inexact differential equation?

6 votes
Accepted

Given positive real numbers $a, b, c$ with $a<b+c$, show that $a/(1+a)<b/(1+b)+c/(1+c)$

6 votes

What is the value of $I=\lim_{n \to \infty} \int_0^1 {{1 + nx^2}\over{(1 + x^2)^n}} \log(2 + \cos(x/n))\,dx.$?

5 votes
Accepted

Show that system is linearly dependent

5 votes
Accepted

Easy way to see that $(x^2 + 5x + 4)(x^2 + 5x + 6) - 48 = (x^2 + 5x + 12)(x^2 + 5x - 2)$?

4 votes

Dynamical systems proofs wanted

4 votes

Integral with bounds

4 votes
Accepted

Does the limit exist for $\lim_{x\to \infty} \frac{x^{\frac{3}{2}}\cdot \arctan(x)}{\sqrt{2x^3+4x^2+x}}$?

4 votes

Fibonacci numbers and recurrence relations

4 votes
Accepted

How to evaluate this Trig integral?

4 votes
Accepted

Solve the following differential equation: $y\frac{dx}{dy}-x=2y^2$, with the initial condition $y(1)=5$.

3 votes
Accepted

Finding general solution for a nonhomogeneous system of equations

3 votes

Proof of integral property

3 votes

If a is an arbitrary integer, then $6|a(a^2+11)$

3 votes

Two complex definite Integrals

1
2 3 4 5
7