A Diophantine Equation @dhdkro

Number of digits of n!

An Equation For Weierstrass Substitution

A Nice and Easy Functional Equation

Solving a Quartic Equation

Another Example of Taylor Series

Can you crack this beautiful equation? – University exam question

USA Math Olympiad question with @skdjfk

A long road to the limit

An algebra problem from Ecuador 2009 TST

Can you solve this tricky exponential equation?

Proving the pq formula for solving quadratic equations

a nice functional equation

2015 Harvard-MIT Math Tournament #25

Find all positive integer n

Everything is possible in math | A tricky algebra question

Integrate x^-x dx

solving equations but they get increasingly more impossible?

1973 USAMO ( System of equations)

Is x^x=0 solvable?

Integrate 1/(1+x^3)