GReyes's user avatar
GReyes's user avatar
GReyes's user avatar
GReyes
  • Member for 3 years, 9 months
  • Last seen this week
  • Irvine, CA
16 votes
Accepted

Quick question on an approximation from physics

14 votes
Accepted

Question about domain of composition of functions?

9 votes

What is the purpose of $\frac{1}{\sigma \sqrt{2 \pi}}$ in $\frac{1}{\sigma \sqrt{2 \pi}}e^{\frac{(-(x - \mu ))^2}{2\sigma ^2}}$?

7 votes
Accepted

$\sin x+\cos x=\frac{5}{4}$, find $\cos(4x)$ without a calculator

7 votes

Is the area of a triangle a function of its perimeter?

6 votes

If $F(x) = f(x)g(x)$, what is th nth derivative of F, that is $F^{n}(x)$, if $f$ and $g$ have derivatives of all orders?

6 votes
Accepted

Why does $f(x,y)= \frac{xy^2}{x^2+y^4}$ have different limits when approaching $(0,0)$ along straight lines vs. along the curve $(1/t^2,1/t)$?

6 votes
Accepted

Complex proof of the Fundamental Theorem of Algebra

5 votes

Can someone explain Dirac Distribution?

5 votes

All norms are equivalent in finite dimensional vector spaces example.

5 votes
Accepted

KKT multipliers and "active" and "inactive" constraints on the generalized Lagrangian $L$

5 votes
Accepted

Which limit is correct? Why does L'Hospital's rule yield a different result?

5 votes

Why isn't $dydx$ equal to $r\cos^2\theta dr\,d\theta$?

5 votes

Proving $\sum_{k=1}^{n}\cos\frac{2\pi k}{n}=0$

5 votes
Accepted

Why does the cube have the fewest facets among (centrally) symmetric polytopes in $\mathbb{R}^n$?

5 votes

Showing that a general Hessian matrix is positive semidefinite

5 votes

How to prove the condition for interior points in convex sets?

4 votes

The sum of $n$ consecutive numbers is divisible by the greatest prime factor of $n$.

4 votes
Accepted

Why do we divide by $ \sqrt{A^2 + B^2} $ to convert a function from the standard form to the normal form?

4 votes

What are the differences between Heat equations and Poisson Equations?

4 votes
Accepted

Some doubts in the evaluation of: limit as $(x,y)\to(0,0)$ of $\frac{\sin xy}{x+y}$

4 votes
Accepted

Implicit equation for the image of immersion $(\cosh(t),\sinh(t))$

4 votes

Cauchy problem $xu_x+yu_y=u+1$ if $u(x,x^2)=x^2$ (concern on the restrictions)

4 votes
Accepted

If $A$ is an idempotent matrix i.e, $A^2=A$, and given that $|A| \ne 0$, prove that $A=I$, where $I$ is the identity matrix.

4 votes
Accepted

Reference request: Source for "Cauchy's Theorem" (?) on integration in elementary functions

4 votes

Lines tangent to a parabola

4 votes
Accepted

$|f(x)-f(y)|\leq \|x-y\|^2$ implies $f$ is constant

4 votes
Accepted

Does adding to degree n polynomial terms with negative exponents still have n roots?

4 votes
Accepted

On the proof of that the only linear operator mapping each element of a complex vector space to an orthogonal element is the $0$ operator

4 votes

Can all covector field be written as a product of a function and a differential of another function?

1
2 3 4 5
22