Lythia's user avatar
Lythia's user avatar
Lythia's user avatar
Lythia
  • Member for 9 years, 7 months
  • Last seen more than 6 years ago
22 votes
Accepted

Proof of $ |a-b| = |b-a| $

14 votes

Show that $B$ is invertible if $B=A^2-2A+2I$ and $A^3=2I$

8 votes
Accepted

the gradient of the product of a scalar by a vector

6 votes
Accepted

Gradient in a rotated reference frame

4 votes

If a matrix $A^2$ is invertible, is $A^3$ invertible?

2 votes

For complex z showing $\cos(z+ \pi) = -\cos(z)$

2 votes
Accepted

Vector calculus - Material derivative in spherical coordinates...

2 votes
Accepted

Derivative of $\frac{x}{\|x\|}$ w.r.t. x where $x\in \mathbb{R}$ ($x \neq \theta_n$)

2 votes

Why doesn't quadratic formula lead to a the correct factored form of the original equation?

2 votes
Accepted

Inverse function $g^{-1}$

2 votes
Accepted

Prove that a classical solution of $-\langle\nabla,A\nabla u\rangle=f$ is also a weak one

2 votes
Accepted

matrix multiplication manipulation

2 votes

Find all possible values of $ a^3 + b^3$ if $a^2+b^2=ab=4$.

2 votes
Accepted

PDF of fx(x) to CDF Fy(y)

2 votes

A question from an engineering undergraduate

2 votes
Accepted

Show that $x^T A x = x^T sym(A) x$

2 votes

Determine the Stress Vector on a plane given the normal?

2 votes
Accepted

Confused about matrix and vector operations, properties.

1 vote

A 2x2 matrix $M$ exists. Suppose $M^3=0$ show that (I want proof) $M^2=0$

1 vote
Accepted

Is my algorithm correct? (Polar decomposition)

1 vote

Equating the general operator to the Laplacian: $Lu=-\Delta u$

1 vote

If $\frac{\partial f}{\partial x}=i\frac{\partial f}{\partial y}$ then $\overline{f }$ is analytic (exercise from Ahlfors' textbook)

1 vote

Gradient of modulus of vector.

1 vote

What is the matrix $\left[ DS(A) \right]$, which gives $\left[ DS(A) \right] H=AH+HA$?

1 vote

Indifferent Tensor Field

1 vote

$\frac{\ln(x^2)}{\ln(x)} = 2$? Why?

1 vote

Calculating the Legendre transform of a function explicitly

1 vote

Converting tensor product from one coordinate to another

1 vote

How do we get the last relation?

0 votes
Accepted

Is every tensor the gradient of a vector?