||James pose la question :
I have the equation: tn = (n)(n+1)/2
Which gives the sequence: 1, 3, 6, 10, 15 etc.
However, I'd like to be able to solve for n.
So that a t of 6 would give me the answer of 3, and t of 10 would give me the answer 4 etc.
Stephen La Rocque and Victoria West lui répond.