Scalar Multiple times $n \times n$ Identity Matrix Proof
10083
Determinant of matrix times a constant.
133017
Prove that $n^n>1\times3\times5\times7\times \dots\times(2n-1)$
33104
Combinatorial Proof with Summation Identity
57981
Alternative proof of $a\times0= 0$
64656
how do you prove that $A\times (B\setminus C) = (A\times B) \setminus (A\times C)$?
30665
Elegant proofs that similar matrices have the same characteristic polynomial?
8627
Number of equivalence classes of $w \times h$ matrices under switching rows and columns
51800
We have matrix $A\in M_{n-1\times n}(\mathbb Z)$ so that the sum of entries in each row is zero. Prove that $\det(AA^T)=nk^2.$
146847
Given a square matrix A of order n, prove $\operatorname{rank}(A^n) = \operatorname{rank}(A^{n+1})$
152932
Proof: $\det\pmatrix{\langle v_i , v_j \rangle}\neq0$ $\iff \{v_1,\dots,v_n\}~\text{l.i.}$
90904
Combinatorial proof of an identity with squared binomial coefficients
52040
"Inverse" of an $n\times k$ matrix.
61483
Prove the following identity combinatorially
137920
Proving an equation with invertible matrices
134162
What is a basis for the space of $n\times n$ Hermitian matrices?
24585
Proving that $\mathbf{W}$+$\mathbf{W^{\perp}}$=$\mathbb{R^{n}}$
82020
basic linear algebra question, proving it is a diagonal matrix and scalar matrix.