MAT - Paper 2015 - Q2
Flashcards
2021-10-10
If you want to prove an expression can’t be a cube, how could you do it?
Show that it can’t lie between two consecutive cubes.
Why can’t $k^3 + 2k^2 + 2k + 1$ be a cube if $k^3 < k^3 + 2k^2 + 2k + 1 < (k + 1)^3$?
Because you can’t have an cube number between two consecutive cube numbers.