1.6.15 Standard formulae for geometric series (A-level only)

A geometric progression has first term $u_1\,$ and common ratio $k$ .

Show that the sum of the first $n\,$ terms of this progression, $S_n$ , can be expressed as

S_n = \frac{u_1(1 - k^n)}{1 - k}

[4]

A geometric progression has first term $u_1\,$ and common ratio $k$ .

Show that the sum of the first $n\,$ terms of this progression, $S_n$ , can be expressed as

S_n = \frac{u_1(1 - k^n)}{1 - k}

[4]

1.6.15 Standard formulae for geometric series (A-level only) Questions