Newbetuts

Let $f: R \to R$ be a map of class $C^1$. Show the set P = $\left\{x \in R : f'(x) \neq 0\right\}$ is open.

Finding $f(B)$, $f^{-1}(C)$ and $f(D)$ when $f: \mathcal P(\mathbb Z)\to \mathcal P(\mathbb Z)$, $f(X)=X'$

Some three consecutive numbers sum to at least $32$

Discrete Mathematics - Logic gates so the lamp can glow

If a student who received an A in probability is chosen at random, what is the probability that he/she also received an A in calculus?

Solving two simultaneous recurrence relations

Solve recurrence for strings that do not contain the substring 101

Which non-Abelian finite groups contain the two specific centralizers? - part II

Is there a closed form or approximation to $\sum_{i=0}^n\binom{\binom{n}{i}}{i}$

Minimum degree of a graph and existence of perfect matching

Visualizing Concepts in Mathematical Logic

Is "empty set" an element of a set?

What problems are easier to solve in a higher dimension, i.e. 3D vs 2D?

What exactly is a countable union?

Elementary number theory in sets

Proof that the sum of the cubes of any three consecutive positive integers is divisible by three.

Proving that $f$ is a bijection from $N$x$N$ to $N$.

New posts in discrete-mathematics

Induction proof on a sequence

Exercise involving DFT

The random variable X has homogeneous distrigution

Let $f: R \to R$ be a map of class $C^1$. Show the set P = $\left\{x \in R : f'(x) \neq 0\right\}$ is open.

Finding $f(B)$, $f^{-1}(C)$ and $f(D)$ when $f: \mathcal P(\mathbb Z)\to \mathcal P(\mathbb Z)$, $f(X)=X'$

Some three consecutive numbers sum to at least $32$

Discrete Mathematics - Logic gates so the lamp can glow

If a student who received an A in probability is chosen at random, what is the probability that he/she also received an A in calculus?

Solving two simultaneous recurrence relations

Solve recurrence for strings that do not contain the substring 101

Which non-Abelian finite groups contain the two specific centralizers? - part II

Is there a closed form or approximation to $\sum_{i=0}^n\binom{\binom{n}{i}}{i}$

Minimum degree of a graph and existence of perfect matching

Visualizing Concepts in Mathematical Logic

Is "empty set" an element of a set?

What problems are easier to solve in a higher dimension, i.e. 3D vs 2D?

What exactly is a countable union?

Elementary number theory in sets

Proof that the sum of the cubes of any three consecutive positive integers is divisible by three.

Proving that $f$ is a bijection from $N$x$N$ to $N$.