User Aleksandr Hovhannisyan - Mathematics Stack Exchange

22 votes

Big-O Notation - Prove that $n^2 + 2n + 3$ is $\mathcal O(n^2)$

answered Jun 7, 2017 at 19:32

5 votes

Probability of getting at least 1 red or green ball

answered Jul 10, 2017 at 18:27

3 votes

Stars and bars with constraints

answered Feb 4, 2018 at 15:19

1 vote

Accepted

Using direct proof, prove that $2^0 + 2^1 + 2^2 + \dots + 2^n = 2^{n+1} - 1$ (no summation, theorems, or induction allowed)

answered May 22, 2023 at 0:58

0 votes

Accepted

Finding the Taylor polynomial for f(x) = sin(x) at x = $\pi$

answered Nov 24, 2016 at 21:22

0 votes

Proof for parallelogram law of vector addition

answered Sep 28, 2019 at 18:28

0 votes

Sieve of Eratosthenes : why $\sqrt n$ work?

answered Apr 8, 2023 at 1:02

0 votes

Prime of form $n^2-4$

answered Mar 2, 2023 at 3:26

0 votes

What is the relationship between modulo and $\log_2$ in this problem?

answered Aug 3, 2018 at 23:34

0 votes

Show that $\gcd(a, 0)$ exists and equals $|a|$ for all $a$ in $\mathbb Z$

answered Nov 19, 2022 at 20:30

0 votes

A particle is moving along $x$-axis whose position is varying with time according to x=-3t+$t^3$. The displacement from t=1 to t=3 is

answered Sep 14, 2019 at 16:49

0 votes

Linear transformations: one-to-one mapping.

answered Sep 14, 2017 at 14:46

0 votes

How much should one pay, answer using expectation of random variable?

answered Jan 31, 2018 at 18:52

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13 Answers

Big-O Notation - Prove that $n^2 + 2n + 3$ is $\mathcal O(n^2)$

Probability of getting at least 1 red or green ball

Stars and bars with constraints

Using direct proof, prove that $2^0 + 2^1 + 2^2 + \dots + 2^n = 2^{n+1} - 1$ (no summation, theorems, or induction allowed)

Finding the Taylor polynomial for f(x) = sin(x) at x = $\pi$

Proof for parallelogram law of vector addition

Sieve of Eratosthenes : why $\sqrt n$ work?

Prime of form $n^2-4$

What is the relationship between modulo and $\log_2$ in this problem?

Show that $\gcd(a, 0)$ exists and equals $|a|$ for all $a$ in $\mathbb Z$

A particle is moving along $x$-axis whose position is varying with time according to x=-3t+$t^3$. The displacement from t=1 to t=3 is

Linear transformations: one-to-one mapping.

How much should one pay, answer using expectation of random variable?