Answers

2016-07-15T19:53:48+08:00
An=A1r^n-1

Sn=A1(1-r^n) ÷ (1-r)


^ means raise to the power
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2016-07-16T07:44:32+08:00
An=a¹rn An,=last term given A¹=first term R=Common ration N=Total means (number of given lines)
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