The familiar Pythagorean 3-4-5 triple gives one solution to (x-1)^n + x^n = (x+1)^n so what about other solutions for x an integer and n= 2, 3, 4 or 5?
Find the positive integer solutions of the equation (1+1/a)(1+1/b)(1+1/c) = 2
Find all 3 digit numbers such that by adding the first digit, the square of the second and the cube of the third you get the original number, for example 1 + 3^2 + 5^3 = 135.
Which is larger, $\cos(\sin x)$ or $\sin(\cos x)$ ? Does this depend on $x$ ?