User DRPR

3

votes

2

answers

79

views

Show that $\operatorname{rank}(A)=\operatorname{rank}(B)$ [duplicate]

linear-algebra matrices

May 8 '18 at 18:26 Jorge Fernández-Hidalgo 90.6k

3

votes

0

answers

171

views

Let $f \colon \mathbb{R} \to \mathbb{R}$ be an infinitely differentiable function

calculus

Apr 27 '18 at 21:49 Community♦ 1

3

votes

1

answer

96

views

Evaluate $\lim_\limits{n\to \infty} e^{-n}\sum_\limits{j=n}^{j=4n} \frac{n^j}{j!}$ [closed]

sequences-and-series limits

Apr 8 '18 at 8:38 Lorenzo B. 2,162

1

3

votes

3

answers

176

views

Prove that $B$ is non singular and that $AB^{-1}A=A$

linear-algebra matrices

Mar 2 '18 at 20:19 Christoph 19.6k

2

votes

3

answers

162

views

Find the solutions to:$\frac{d^2y}{dx^2}=\left(\frac{dy}{dx}\right)^2$.

ordinary-differential-equations

May 17 '18 at 12:38 Martin Sleziak 52k

2

votes

5

answers

78

views

Evaluate $\lim_{x\to \infty}(\log x)^{1/x}$

limits

May 14 '18 at 10:08 farruhota 29.2k

1

2

votes

2

answers

141

views

18 boys and 2 girls are made to stand in a random order.Let X be the number of boys standing in between two girls .

probability combinatorics

May 10 '18 at 16:33 Mike Earnest 39.9k

2

votes

2

answers

114

views

Find the maximum likelihood estimator of b (Regression coefficient)

probability statistics maximum-likelihood linear-regression

Apr 30 '18 at 8:08 the_fox 5,462

2

votes

2

answers

136

views

Let $ X $ Be the Number of Faces that Never Showed Up in $ n $ Dice Rolls - What's $ \mathbb{E} \left[ X \right] $?

probability expectation

Apr 23 '18 at 7:36 Royi 6,420

2

votes

2

answers

197

views

If $7$ balls are distributed among three urns, what is the probability that one urn remains empty?

probability combinatorics

Apr 4 '18 at 3:10 EightZeroEight 11

2

votes

2

answers

76

views

$f(x) = g(x)$ for exactly two values of $x$

calculus real-analysis

Mar 30 '18 at 10:44 Ski Mask 1,833

1

2

votes

2

answers

101

views

$\lim_{n\to\infty} \left(1+\frac{2}{n}\right)^{n^2} e^{-2n}$

real-analysis sequences-and-series

Mar 28 '18 at 16:13 Xander Henderson♦ 21.1k

1

2

votes

1

answer

122

views

variance of regression estimators

statistics regression linear-regression

Mar 24 '18 at 18:09 Michael Hardy 246k

1

2

votes

1

answer

96

views

Combinatorics -average value

probability combinatorics

Sep 22 '17 at 6:56 Community♦ 1

1

vote

1

answer

36

views

Show thatIf f attains its maximum at some point in L, show that f is a constant function.

combinatorics contest-math integer-lattices extremal-combinatorics

Mar 20 at 14:51 Aqua 78.3k

1

vote

2

answers

348

views

A box has an unknown number of tickets serially numbered 1,2,…,N. Two tickets are drawn using simple random sampling without replacement

statistics self-learning estimation sampling

Aug 26 '18 at 9:03 manjeet singh 1

1

vote

2

answers

52

views

Suppose $X_1 ,X_2 \text{ and } X_3$ are iid normal random variables . Then

probability-theory probability-distributions independence

Aug 26 '18 at 7:51 J.G. 95.6k

1

vote

1

answer

52

views

I am asked to find the equation of tangent to the curve $y=\sin^2\left(\frac{\pi x^3}{6}\right)$ at $x=1$

calculus algebra-precalculus

May 14 '18 at 17:10 Lorenzo B. 2,162

1

vote

0

answers

185

views

Suppose there are 9 white balls and 3 red balls. A,B,C take turns to pick a ball without replacement . The first person to get a red ball wins.

probability

May 11 '18 at 14:30 DRPR 713

1

vote

2

answers

79

views

$P(X \le 2Y \le 3Z)= ?$

probability

May 10 '18 at 5:58 callculus 25.6k

1

vote

2

answers

65

views

Let $E = \{1,2,\ldots,n \}$, where n is a positive integer.

linear-algebra vectors

May 8 '18 at 23:06 SK19 2,723

2

1

vote

0

answers

71

views

Show that $X_{(n)}$ is a sufficient for $\theta$

statistics self-learning statistical-inference

Apr 26 '18 at 7:02 DRPR 713

1

vote

3

answers

171

views

Simple Linear regression assumption

statistics definition regression linear-regression

Mar 23 '18 at 0:48 V. Vancak 13.5k

1

vote

1

answer

23

views

Decomposition of $z= x+y$

linear-algebra matrices eigenvalues-eigenvectors symmetric-matrices

Oct 28 '17 at 6:56 TheSimpliFire 21.3k

1

vote

1

answer

120

views

Using central limit theorem , evaluate

probability central-limit-theorem

Oct 6 '17 at 21:03 H. H. Rugh 28k

0

votes

2

answers

83

views

Find the symmetric subsets of $B = \{1,2,3,4\}$

combinatorics discrete-mathematics elementary-set-theory relations

Jun 14 at 13:56 Aqua 78.3k

0

votes

2

answers

389

views

In how many permutations of $1,2,3…100$ will the 25th number be the minimum of the first 25 numbers, and likewise for the 50th of the first 50?

combinatorics permutations

Sep 17 '19 at 3:54 Priyankashi Barnwal 1

0

votes

1

answer

410

views

Finding an unbiased estimator of$ e^{−2λ}$ for Poisson distribution

probability statistics statistical-inference estimation

Sep 11 '18 at 0:08 Michael Hardy 246k

0

votes

2

answers

38

views

$\text{Prove that if} \sum_{i=1}^{m}|a_i - x|=\sum_{i=1}^{n}|b_i - x|$ Then $\text{ m=n and }a_j = b_j \text{for}0\le j\le n$

calculus sequences-and-series algebra-precalculus

May 29 '18 at 12:39 xpaul 32k

0

votes

2

answers

181

views

orthogonal projection by matrices

linear-algebra orthonormal

May 21 '18 at 1:56 amd 47.2k

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39 Questions

Show that $\operatorname{rank}(A)=\operatorname{rank}(B)$ [duplicate]

Let $f \colon \mathbb{R} \to \mathbb{R}$ be an infinitely differentiable function

Evaluate $\lim_\limits{n\to \infty} e^{-n}\sum_\limits{j=n}^{j=4n} \frac{n^j}{j!}$ [closed]

Prove that $B$ is non singular and that $AB^{-1}A=A$

Find the solutions to:$\frac{d^2y}{dx^2}=\left(\frac{dy}{dx}\right)^2$.

Evaluate $\lim_{x\to \infty}(\log x)^{1/x}$

18 boys and 2 girls are made to stand in a random order.Let X be the number of boys standing in between two girls .

Find the maximum likelihood estimator of b (Regression coefficient)

Let $ X $ Be the Number of Faces that Never Showed Up in $ n $ Dice Rolls - What's $ \mathbb{E} \left[ X \right] $?

If $7$ balls are distributed among three urns, what is the probability that one urn remains empty?

$f(x) = g(x)$ for exactly two values of $x$

$\lim_{n\to\infty} \left(1+\frac{2}{n}\right)^{n^2} e^{-2n}$

variance of regression estimators

Combinatorics -average value

Show thatIf f attains its maximum at some point in L, show that f is a constant function.

A box has an unknown number of tickets serially numbered 1,2,…,N. Two tickets are drawn using simple random sampling without replacement

Suppose $X_1 ,X_2 \text{ and } X_3$ are iid normal random variables . Then

I am asked to find the equation of tangent to the curve $y=\sin^2\left(\frac{\pi x^3}{6}\right)$ at $x=1$

Suppose there are 9 white balls and 3 red balls. A,B,C take turns to pick a ball without replacement . The first person to get a red ball wins.

$P(X \le 2Y \le 3Z)= ?$

Let $E = \{1,2,\ldots,n \}$, where n is a positive integer.

Show that $X_{(n)}$ is a sufficient for $\theta$

Simple Linear regression assumption

Decomposition of $z= x+y$

Using central limit theorem , evaluate

Find the symmetric subsets of $B = \{1,2,3,4\}$

In how many permutations of $1,2,3…100$ will the 25th number be the minimum of the first 25 numbers, and likewise for the 50th of the first 50?

Finding an unbiased estimator of$ e^{−2λ}$ for Poisson distribution

$\text{Prove that if} \sum_{i=1}^{m}|a_i - x|=\sum_{i=1}^{n}|b_i - x|$ Then $\text{ m=n and }a_j = b_j \text{for}0\le j\le n$

orthogonal projection by matrices