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math.n00b
  • Member for 8 years, 6 months
  • Last seen more than 5 years ago
14 votes
Accepted

Positive and negative complex numbers?

11 votes
Accepted

How to prove the inequality $\det (AA^T) \ge 0$?

5 votes

Exercise on inner products

4 votes
Accepted

What is this notation? Cyclic group $\mathbb{Z}^*_8$

4 votes
Accepted

Existence of isomorphism between groups of upper triangular matrices.

4 votes

Why $\lim_{z\to\infty}\frac{\sin(z)}z$ doesn't exist?

4 votes
Accepted

How do I prove $\sec^2 \frac{a}{2}=\frac{2\sec a}{1+\sec a}$?

4 votes
Accepted

Finding radius of convergence using root test

3 votes
Accepted

Proof that the set $M=\{ (x_1,x_2)\in \mathbb{R}_{++}^2 \mid x_1 x_2\geq k \}$ is convex

3 votes

Is $a^T M b = b^T M a$?

3 votes

Ok, I know what does linear independence mean but why should I care?

3 votes

How come $1^{\infty}$ = undefined, while $2^{\infty} = \infty$ and $0^{\infty} = 0$?

2 votes
Accepted

Center of $G/Z(G)$.

2 votes

What is the difference between $\mathbb Z_n$ and $\mathbb Z / n \mathbb Z$?

2 votes

Is it normal that a pure math student doesn't know vector analysis?

2 votes

Where's the problem with a false "proof": $\;1^0 = 1^2 \overset{?}\implies 0 = 2$

2 votes

a question about relationship between characteristic polynomial and minimal polynomial

2 votes

For a differentiable map $f: \mathbb{R^n}\to \mathbb{R^n}$, Show that $f^*({dy_1 \wedge\cdots \wedge dy_n})=\det(df)dx_1\wedge \cdots\wedge dx_n$

2 votes

Skew-symmetric matrix subspace dimension and basis

2 votes

What is Derivative of order more than one?

2 votes

How to show that $m^*(A \cup B) + m^*(A \cap B) \leq m^*(A)+m^*(B)$ for any $A,B \subseteq \mathbb{R}$?

1 vote

Basis for space of matrices in $\mathbb M_2(\mathbb R)$

1 vote
Accepted

Matrices as sets of vectors

1 vote

Euclidean space and Euclidean geometry

1 vote

Find which differentiable function is determined by this power series

1 vote

Understanding substitution to compute primitive

1 vote

Proofs of matrix properties

1 vote
Accepted

Help in understanding proof of Möbius Inversion Formula

1 vote

Showing $f$ is monotonely decreasing

1 vote
Accepted

Why is $\phi$ an epimorphism of rings?