Recent content by YASuperhero

I don't understand. That is the equation I have and that will give me a. But I have a and x. What I need to find out is n. What am I missing?

Homework Statement I'm trying to find out the equation for how to find out where a number falls in a sequence. An example sequence would be 3, 9, 18, 30, 45, 63, 84, 108, 135, 165... 108 is the 8th number in that sequence. Homework Equations If I use the equation (xn+xn^2)/2 (x = 3...