Posted by Joel on September 09, 2002 at 22:21:15:
In Reply to: Quadratics posted by kimmay on September 09, 2002 at 18:40:11:
: I have a sequence of terms and am required to come up with a function.. apparently quadratic.. need help..
: {1,3,6,10,15,21,28,36,45...}
: thanks
It's difficult to write this without using symbols & subscripts but I think this is the way to describe your function:
a sub n = Sum[from n=1 to n]n
In English:
The members of your set are {a sub 1, a sub 2 ... a sub n}
a sub 1 is 1
a sub 2 is 1 + 2
a sub 3 is 1 + 2 + 3
etc