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cnmesr
  • Member for 7 years, 8 months
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73 votes
15 answers
19k views

Solving $DEF+FEF=GHH$, $KLM+KLM=NKL$, $ABC+ABC+ABC=BBB$

42 votes
2 answers
14k views

How to efficiently use a calculator in a linear algebra exam, if allowed

11 votes
5 answers
2k views

How can you prove $\frac{n(n+1)(2n+1)}{6}+(n+1)^2= \frac{(n+1)(n+2)(2n+3)}{6}$ without much effort?

10 votes
5 answers
3k views

Diagonalized matrix - Is each column an eigenvector?

9 votes
3 answers
10k views

How can you comment this calculation step to avoid points deduction by teacher?

8 votes
4 answers
4k views

True or false: Every real homogeneous linear system of equation which has more than one solution has infinite solutions

6 votes
2 answers
5k views

Convergent or divergent: $\sum_{k=1}^{\infty}\frac{2^{k}\cdot k!}{k^{k}}$ [duplicate]

5 votes
1 answer
34k views

Calculate the image and a basis of the image (matrix)

5 votes
3 answers
3k views

Is this subset a basis of the vector space?

5 votes
1 answer
4k views

From $p_{1},p_{2},p_{3}$ choose a basis $B$ for $W$

4 votes
1 answer
203 views

Integrate $\int{ e^{{x}^{2}-x} \cdot x \cdot e^x} dx$

4 votes
7 answers
157 views

Is $|x| \cdot |x| = |x^2| = x^2$?

4 votes
1 answer
309 views

Are these two functions numerically stable?

4 votes
1 answer
1k views

There is a phone number with $10$ digits. What's the probability that each digit occurs exactly once?

4 votes
2 answers
1k views

Determine the distribution function of this density function

4 votes
3 answers
1k views

Calculate: $\frac{1}{2! \cdot 2} + \frac{1}{4! \cdot 4} + \frac{1}{6! \cdot 8} + \frac{1}{8! \cdot 16} + ...$

4 votes
3 answers
106 views

Calculate $\sum_{k=2}^{\infty}\frac{3}{5^{k-1}}$

4 votes
4 answers
2k views

Is it possible / allowed to use L'Hôpitals rule for products?

4 votes
1 answer
154 views

Limit of sequence $\lim_{n\to\infty}\frac{1+(\sqrt{n}+1)^{3}+2\sqrt{n}}{n+\sin(n)}$

4 votes
5 answers
178 views

Analyze if this series converges: $\sum_{n=0}^{\infty}\frac{n^{2}+1}{n!}$

4 votes
3 answers
117 views

Prove or disprove: $\bigcap_{n\in\mathbb{N}}\left[-\frac{1}{n!},1+\frac{1}{2^{n}}\right]=\left \{ 1,2 \right \}$

4 votes
6 answers
804 views

Proof by induction: $2^{n} < n!$ [duplicate]

3 votes
3 answers
3k views

How can I know whether the point is a maximum or minimum without much calculation?

3 votes
2 answers
181 views

Calculate: $x=2^{12} \pmod{13}$ in $\mathbb{Z}_{13}$

3 votes
3 answers
681 views

Injective, surjective or bijective?: $f: \mathbb{R}^{2} \rightarrow \mathbb{R}^{2}, (x,y) \mapsto (x+y,x+y^{2})$

3 votes
2 answers
358 views

Are these two statements true or false?

3 votes
3 answers
479 views

Limit of the sequence $\lim_{n\rightarrow \infty}n\left ( 1-\sqrt{1-\frac{5}{n}} \right )$, strange result

3 votes
3 answers
112 views

How would you proof that this series is convergent (no solution needed)?

3 votes
2 answers
69 views

Show that the following equation has got exactly one solution for each $C>0$

3 votes
9 answers
962 views

Calculate the limit: $\lim_{n\rightarrow\infty}\left(\frac{1^{2}+2^{2}+...+n^{2}}{n^{3}}\right)$

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