Remarks.
Notice that for (b) since the common ratio \(r\) is of magnitude less than \(1\), the following representation
\[S_n = \frac{a(1-r^n)}{1-r}\]
is preferred as both&nbsp;\((1-r^n)\) and \((1-r)\) will be positive.

Notice that for (b) since the common ratio \(r\) is of magnitude less than \(1\), the following representation

is preferred as both \((1-r^n)\) and \((1-r)\) will be positive.

Geometric Progression

APGP

International Baccalaureate Higher Level Mathematics

Remarks concerning choice of formulae

Remarks concerning choice of formulae