Locate the discontinuities of the function. $$f(x) = \ln(\tan(x)^2)$$ Question is looking for a, $x =$ value.

Let $\{u_n\}_{n\in \mathbb N}$ be an orthonormal set in $H$ (Hilbert space). How prove that the set $\displaystyle Q=\{x\in H :\ x=\sum_{i=1}^{\infty}{c_n...

Suppose that $X$ is a metric space. Show that if $D$ is a dense $G_{\delta}$ set, then $D$ is comeagre, that is, countable intersection of dense sets. My ...

I know its a simple question but its hard to google these symbols. Anyways, anyone care to explain what $P(A \triangle B)$ means? I haven't seen this...

I'm going through the process of induction and when I'm attempting to prove $P_{k+1}$ I keep getting $2(3A-\frac32)$, where $A$ is an integer an...

Possible Duplicate: Proof for an integral involving sinc function How do I show that $\int_{-\infty}^\infty \frac{ \sin x \sin nx}{x^2} \ dx = \pi$? $\int...

Given $A$ is a skew-hermitian, ( i.e $A^H = -A$ ) then how do you prove the matrix exponential $e^A$ is unitary. To prove the unitary property of the matr...

I got this question in my maths paper Test the condition for convergence of $$\sum_{n=1}^\infty \frac{1}{n(n+1)(n+2)}$$ and find the sum if it exists. I m...

What is difference between normalization and magnitude of a vector. We compute them with same formula but i don't know any geometric difference betwe...

I'm having trouble articulating my difficulty, but here's my best shot. Thanks in advance for any light you can shed. I understand that a defini...