Intereting Posts

the exact value of $\displaystyle\sum_{n=2}^\infty\arcsin{\left(\dfrac{\sqrt{n}-\sqrt{n-1}}{\sqrt{n^2-1}}\right)}$
Is '10' a magical number or I am missing something?
Prove that if $a\equiv b \pmod m $ , then $a \bmod m = b \bmod m$
What is the joint distribution of two random variables?
Laplace transform of $\cos(at)$
Roots of Legendre Polynomial
Deriving the formula of the Surface area of a sphere
$\operatorname{Im} A = (\operatorname{ker} A^*)^\perp$
Does a continuous and 1-1 function map Borel sets to Borel sets?
Does the definition of a vector field include maps from $\mathbb{R}^n \to \mathbb{R}^m$ or only maps from $\mathbb{R}^n \to \mathbb{R}^n$?
Minimal polynomial of $T(A) = A^t – A$
How to show $f'(0)$ exist and is equal to $1$?
CRC computation
General term of a double dimensional sequence
Characteristic function of Normal random variable squared

The question is so simple, but I cannot find the answer.

Is $M_i$ (usually) the $i^{\text{th}}$ column of matrix $M$? Or the $i^{\text{th}}$ row?

Since $M_{ij}$ is the $j^{\text{th}}$ element of the $i^{\text{th}}$ row, I would say $M_i$ is the row.

On the other hand we usually work with column vectors and it is therefore unusual to take a row from a matrix and it would be illogical to have a simple notation for something that is used less often.

- Can every $T$-stable subspace be realised as the kernel of another linear operator that commutes with$~T$?
- Projection of a vector
- How to find a nonzero $2 \times 2$ matrix whose square is zero?
- Block diagonalizing two matrices simultaneously
- Existence of least squares solution to $Ax=b$
- Number of $(0,1)$ $m\times n$ matrices with no empty rows or columns

If $M_i$ is the $i^{\text{th}}$ row, how would I get the $i^{\text{th}}$ column? Surely not $(M^T)_i$!

- If $\operatorname{rank}(A)=m$, can we say anything about $\operatorname{rank}(AA^t)$?
- Error in argument regarding the Cayley Hamilton theorem
- Left/Right Eigenvectors
- Mathematical notation
- What's so special about the 4 fundamental subspaces?
- What does the function f: x ↦ y mean?
- In-place inversion of large matrices
- Proof of the conjecture that the kernel is of dimension 2, extended
- Eigenvalues of $A$ and $A + A^T$
- Properties of invertible matrices

- Example of non-trivial number field
- How to show $ a,b,c \in \mathbb R , z \in \mathbb C , az^2 + bz + c = 0 \iff a\bar{z}^2 + b\bar{z} + c = 0$?
- Infinite sets don't exist!?
- Formal proof of Lyapunov stability
- Number of all bijective functions from A to A.
- Birthday-coverage problem
- Show that the union of two sets of measure zero, has a measure zero
- Eigenvalues of doubly stochastic matrices
- Non isomorphic groups who product with Z is isomorphic
- Equality in Young's inequality for convolution
- What are some applications outside of mathematics for algebraic geometry?
- prove that $\operatorname{lcm}(n,m) = nm/\gcd(n,m)$
- how to do such stochastic integration $dS = a S^b dt + c S dW$?
- covering spaces and the fundamental groupoid
- Find Galois Group