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Math 11

General Term tn=t1+d(n-1)

Arithmetics sum Sn=n(t1+tn)/2

General Term tn=1×r^2-1

Geometric sum  Sn=t1(1-r^)/1-r, r≠0

Infinite Geometric sum S∞=t1/1-r

 

I learned these formula.