Skip to main content
Tobias Kienzler's user avatar
Tobias Kienzler's user avatar
Tobias Kienzler's user avatar
Tobias Kienzler
  • Member for 13 years, 10 months
  • Last seen more than a month ago
28 votes

How can I understand and prove the "sum and difference formulas" in trigonometry?

14 votes

Is there a formula similar to $f(x+a) = e^{a\frac{d}{dx}}f(x)$ to express $f(\alpha\cdot x)$?

13 votes
Accepted

What is the Laplace operator's representation in 3-sphere-coordinates?

11 votes
Accepted

Is there a general formula for the derivative of $\exp(A(x))$ when $A(x)$ is a matrix?

8 votes

Collection of surprising identities and equations.

7 votes

Why rationalize the denominator?

6 votes

What is "Bra" and "Ket" notation and how does it relate to Hilbert spaces?

6 votes
Accepted

Generating function for the sequence $1,1,3,3,5,5,7,7,9,9,\ldots$

5 votes

Numerical solution of an integral equation

5 votes

Why does factoring eliminate a hole in the limit?

5 votes
Accepted

Can any meromorphic function be represented as a product of zeroes and poles?

5 votes

Is it possible to construct a strictly monotonic sequence of all rational numbers?

4 votes
Accepted

Is there a closed form expression for the Taylor series of exp((f(z))?

4 votes

Given the product of a unitary matrix and an orthogonal matrix, can it be easily inverted _without_ knowing these factors?

4 votes

How to properly translate the coefficients of a Taylor series?

4 votes
Accepted

Determining the action of the operator $D\left(z, \frac d{dz}\right)$

4 votes

What is the easiest known expression for inverse of Laplace transform?

3 votes

Is there a continuous bijection between an interval $[0,1]$ and a square: $[0,1] \times [0,1]$?

3 votes

How is the set of all programs countable?

3 votes
Accepted

What is the Moore-Penrose pseudoinverse for a hermitian block-matrix with one zero block?

3 votes

Should I be afraid of using known identities that I can't prove?

3 votes

Is arrow notation for vectors "not mathematically mature"?

3 votes
Accepted

What is the Dirac Delta distribution of functions with non-simple roots?

2 votes
Accepted

Angles in a 3D ball of hexagons and squares (truncated octahedron)

2 votes

Is there a word similar to "iff" meaning "one and only one"?

2 votes
Accepted

Complex solution to Euler-Lagrange equation?

2 votes

What equation can produce these curves?

2 votes

What's the inverse of the Weierstrass-Mittag-Leffler-Transform $\exp\left[g(z) + \int_\mathbb C f(y)\ln(z-y)\,dy\right]$?

2 votes

How to minimize this non-linear function?

2 votes

How to switch to a Laurent series' next convergence ring?