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Twenty-six colours
  • Member for 5 years, 4 months
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10 votes
3 answers
20k views

Derivative and partial derivative of complex functions

8 votes
2 answers
4k views

How does proof by contradiction work?

7 votes
2 answers
5k views

Inverse Function Theorem and global inverses

5 votes
1 answer
7k views

What does it mean if divergence of a vector field is zero?

5 votes
3 answers
704 views

Simplifying the sum $\sum\limits_{t=1}^{n} t(t+1)v^t$

5 votes
1 answer
6k views

the 2-D divergence theorem and Green's Theorem

5 votes
2 answers
77 views

Condition on a matrix so that its determinant is $2$

4 votes
4 answers
1k views

Fractional Linear Transformations and their matrix form

4 votes
1 answer
420 views

Simple connectedness of an ellipse

4 votes
2 answers
7k views

Definition of a "region"

4 votes
2 answers
344 views

"Note that connectedness is not defined for closed sets" explanation

4 votes
0 answers
46 views

Is this an OK proof to show that eigenvectors of a symmetric matrix are orthogonal?

4 votes
2 answers
222 views

Proving $\int_{0}^\pi \frac{2\cos 2\theta + \cos 3\theta}{5+4\cos\theta} = \frac{\pi}{8}$

3 votes
3 answers
1k views

Why is the dot product of two vectors $\mathbf{x},\mathbf{y}$ the same as $x^T y$?

3 votes
3 answers
232 views

solving $\cos z + \sin z = i$

3 votes
1 answer
685 views

Show that $E(Z^p) = p \int_0^\infty (1-F_Z(x))x^{p-1} \, dx$ for every $p>0$ and nonnegative random variable $Z$ [duplicate]

3 votes
3 answers
70 views

Is this a valid proof to prove that if $a_n$ converges, then $a_{n+1}-a_{n}$ converges to $0$? by definition

3 votes
2 answers
18k views

Multivariate Chain Rule and second order partials

3 votes
1 answer
935 views

Intuition on why a field is not conservative

3 votes
3 answers
689 views

$\sqrt{z+1}\sqrt{z-1} = -\sqrt{z^2 - 1}$ when $\Re(z) < -1$

3 votes
3 answers
212 views

Showing that $f$ is linear function if $\forall z \in \mathbb{C}$, $|f(z)| \leq 1 + |z|$.

3 votes
3 answers
297 views

Proving $|\cos z\ |^2 + |\sin z\ |^2 \geq 1$

3 votes
1 answer
11k views

Solving $\cos z = 2$

3 votes
1 answer
68 views

Is it possible to define an inner product in this vector space to make it an inner product space?

3 votes
2 answers
693 views

Limits in complex analysis

3 votes
3 answers
747 views

Image of a circle under a complex valued function

3 votes
2 answers
126 views

The exponential of a straight line is a straight line if and only if the line is horizontal

2 votes
2 answers
466 views

Complex roots of polynomials, proving this particular property

2 votes
2 answers
215 views

Inequality for a complex root of a polynomial

2 votes
5 answers
484 views

Intuition why the function $f(z) = \frac{1}{z}$ maps lines to circles

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