Is there a common notation for enumerating a set? For example if $A=\{2,4,6,\ldots,n \}$ is the set of even numbers, I would like to know the notation tha...

NOTE: There is another question asking "What is a Lattice?" but when reading the question, it has to do with programming, and that is not what my question...

I need to prove the continuity of $f(x)=\log x$ using a $\epsilon-\delta$ proof These is what I have so far but am not sure how to continue $|\log x-\log ...

So probability of getting $1$ ace (the one dot in dice) = $1/6$ i.e. in one out of six times we will get an ace. But when we calculate the probability of ...

I would like know whether a circle is intersecting an ellipse. Here ellipse equation is $$Ax^2 + Bxy + Cy^2 + dx+ey + 1 = 0,$$ and the circle equation is ...

The joint density function of $X$ and $Y$ is given by $f(x,y) = xe^{-x(y+1)}$, $x > 0, y > 0$. (a) Find the conditional density of $X$, given $Y = y...

Find the value(s) of $k$ for which the equation, $(x+2)(x+k)=-1$, has equal roots. (I cannot get the two values as stated in the answer $k=0$ and $k=4$. M...

The Birthday Problem: given $n$ people (typically $n<365$), what is the probability that some pair of them share a birthday (omitting Feb 29th, for sim...

I need to prove that $\sin(x) > \frac{x}{2}$ if $0<x<\pi/2$ I've started working with the derivative, but if it's possible, I'd ra...

$2017 /1= 2017$, a prime; $2018/2 = 1009$, a prime; and $2019/3 = 673$, a prime. Call such a sequence a trio. If $2020/4 = 505$ were prime, then we would ...