User Curious

5 votes

How can I prove the last digit of $(2^{121985292}-1)$ is $5$

answered Dec 14, 2014 at 1:16

4 votes

Why use neighborhood to define boundary? Not open ball?

answered Aug 10, 2016 at 4:28

3 votes

Accepted

How many ways can a number be written as a sum of two non negative integers?

answered Dec 11, 2018 at 5:52

3 votes

Accepted

Conceptual question on differentiation in calculus?

answered Jan 26, 2015 at 2:47

3 votes

limit $\lim_{n\to \infty }\sum_{k=1}^{n}\frac{k}{k^2+n^2}$

answered Sep 22, 2015 at 15:03

3 votes

Is there a more systematic approach to solving this inequality?

answered Sep 23, 2015 at 4:31

3 votes

Proving a group with five elements is abelian (commutative)

answered Dec 12, 2015 at 10:04

3 votes

Permutation and Combination 3

answered May 7, 2015 at 10:51

2 votes

Accepted

root of unity, prove relationship

answered Nov 2, 2014 at 15:31

2 votes

Accepted

A and B likely to contradict each other in stating same fact?

answered Feb 5, 2015 at 9:38

2 votes

Accepted

rank of a matrix?

answered Apr 3, 2015 at 6:09

2 votes

Rearrange letters in "ENGINE" so no letter appears next to itself

answered Dec 11, 2015 at 10:36

1 vote

Conceptual question on differentiation in calculus?

answered Jan 26, 2015 at 2:18

1 vote

Limits using L'Hopital's rule $\lim_{x\to0^+} (x^{x^x-1})$

answered Sep 2, 2016 at 11:01

1 vote

Find number of five digit natural numbers using digits $1,2,3,4,5$ such that consecutive digits do not appear together

answered Dec 11, 2018 at 10:09

1 vote

What is the remainder when $1995! -1$ is divided by $100 * 101$?

answered Dec 11, 2018 at 6:18

1 vote

Accepted

The probability of remaining cups of soda in an urn according to a uniform distribution

answered Nov 15, 2016 at 4:49

1 vote

Accepted

How to prove that $\lim_{x\to \pi/2} (\tan x)^{\tan2x}=1$

answered Nov 30, 2014 at 13:19

1 vote

How to solve $\lim\limits_{x\to 0} \frac{x - \tan(x)}{x^2}$ Without L'Hospital's Rule?

answered Jan 12, 2015 at 8:15

1 vote

Accepted

Prove that $\sum_{i=1}^{i=n} \frac{1}{i(n+1-i)} \le1$

answered Jul 13, 2015 at 4:15

1 vote

Prove that $\sum_{i=1}^{i=n} \frac{1}{i(n+1-i)} \le1$

answered Jul 13, 2015 at 5:10

1 vote

Why does this sum converge?

answered Jul 18, 2015 at 19:49

1 vote

inner product question <,>

answered Mar 6, 2015 at 1:02

1 vote

probability of having 2 boys given at least 1 is a boy

answered Jul 13, 2020 at 6:06

0 votes

2 Cards are drawn from a deck of cards. What is the probability of having drawn a black card OR an ace?

answered Jan 15, 2015 at 6:07

0 votes

Proving that rational numbers are dense

answered Jan 22, 2015 at 4:42

0 votes

How can I show that $\lim_{n\to\infty} 2^n \left( \frac{n}{n+1} \right ) ^{n^2} = 0$?

answered Jan 7, 2015 at 13:12

0 votes

Open cover for $(0, 1)$

answered Dec 15, 2014 at 6:22

0 votes

counting measure on naturals not equal to limit

answered Dec 18, 2014 at 5:25

0 votes

Four men go into a restaurant and leave their umbrellas at the door

answered Dec 13, 2018 at 16:26

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35 Answers

How can I prove the last digit of $(2^{121985292}-1)$ is $5$

Why use neighborhood to define boundary? Not open ball?

How many ways can a number be written as a sum of two non negative integers?

Conceptual question on differentiation in calculus?

limit $\lim_{n\to \infty }\sum_{k=1}^{n}\frac{k}{k^2+n^2}$

Is there a more systematic approach to solving this inequality?

Proving a group with five elements is abelian (commutative)

Permutation and Combination 3

root of unity, prove relationship

A and B likely to contradict each other in stating same fact?

rank of a matrix?

Rearrange letters in "ENGINE" so no letter appears next to itself

Conceptual question on differentiation in calculus?

Limits using L'Hopital's rule $\lim_{x\to0^+} (x^{x^x-1})$

Find number of five digit natural numbers using digits $1,2,3,4,5$ such that consecutive digits do not appear together

What is the remainder when $1995! -1$ is divided by $100 * 101$?

The probability of remaining cups of soda in an urn according to a uniform distribution

How to prove that $\lim_{x\to \pi/2} (\tan x)^{\tan2x}=1$

How to solve $\lim\limits_{x\to 0} \frac{x - \tan(x)}{x^2}$ Without L'Hospital's Rule?

Prove that $\sum_{i=1}^{i=n} \frac{1}{i(n+1-i)} \le1$

Prove that $\sum_{i=1}^{i=n} \frac{1}{i(n+1-i)} \le1$

Why does this sum converge?

inner product question <,>

probability of having 2 boys given at least 1 is a boy

2 Cards are drawn from a deck of cards. What is the probability of having drawn a black card OR an ace?

Proving that rational numbers are dense

How can I show that $\lim_{n\to\infty} 2^n \left( \frac{n}{n+1} \right ) ^{n^2} = 0$?

Open cover for $(0, 1)$

counting measure on naturals not equal to limit

Four men go into a restaurant and leave their umbrellas at the door