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qed
  • Member for 13 years, 7 months
  • Last seen more than 1 year ago
13 votes
8 answers
6k views

Fit a equilateral triangle on three arbitrary parallel lines with an edge and compass

10 votes
5 answers
15k views

Prove concurrency of triangle altitudes with vector algebra?

7 votes
2 answers
528 views

Expectation of joint life span

7 votes
1 answer
992 views

Equivalence of another formula for the number of $r$-combinations with repetition allowed

6 votes
7 answers
7k views

A general formula for $\sum (k-1)(k-2)(k-3)$?

6 votes
4 answers
1k views

Continuity at a point implies continuity on an interval?

5 votes
4 answers
2k views

Rigorously prove that the tangent line is indeed tangent?

5 votes
1 answer
6k views

How is the Erlang pdf derived?

5 votes
2 answers
3k views

Spatially invariant systems

3 votes
3 answers
3k views

Function defined on a closed interval must be bounded?

3 votes
0 answers
180 views

Books on n-dimensional euclidian geometry?

3 votes
1 answer
125 views

Is there a geometric concept describing this?

2 votes
1 answer
120 views

An integral similar to binomial formula?

2 votes
2 answers
64 views

Orthonormal basis, decompse then add back

2 votes
0 answers
81 views

A vector with fixed correlation with existing vector, is it always possible?

2 votes
1 answer
111 views

Describing a third variable with two other variables, using combination of elementary functions.

2 votes
1 answer
923 views

Is the Cartesian product of an infinite number of $\mathbb{Z}^+$ countable?

2 votes
3 answers
882 views

Limit of this power function when the base tends to infinity

2 votes
1 answer
363 views

Product in category theory

1 vote
4 answers
333 views

Do $f_{xx}$ and $f_{yy}$ always have the same sign?

1 vote
2 answers
512 views

Functor over sets of functions

1 vote
0 answers
20 views

Are the definitions of convolution here contradict each other?

1 vote
1 answer
1k views

Get number of vertices when number of internal vertices is known ofr a full binary tree

1 vote
1 answer
337 views

Exercise 2.13 from a computational introduction to number theory and algebra

1 vote
1 answer
2k views

Linear regression: b1 has the minimum variance among all unbiased linear estimators of beta1

1 vote
1 answer
105 views

An integral with limits being a funtion of a parameter.

1 vote
1 answer
59 views

Probability of a label appearing on a frazzle

1 vote
1 answer
424 views

Probability of $\lambda$ given k, in Poisson distribution.

1 vote
5 answers
1k views

Prove the existence of a largest integer less than or equal to a rational number

1 vote
0 answers
213 views

Infinite number of primes in the sequence $1+t^2$? [duplicate]