The nth term of a G.P. whose first term is a and common ratio is r, is given by :

1. T_n = ar^{n + 1}

2. T_n = ar^{1 - n}

3. T_n = ar^{n - 1}

4. T_n = $\dfrac{a}{r^{\,n-1}}$

If the first term, common ratio and the last term of a G.P. are a, r and l respectively, then the nth term from the end of the G.P. is given by :

1. lr^{n - 1}

2. lr^{1 - n}

3. $\dfrac{l}{r^{1 - n}}$

4. $\dfrac{l}{r^{n + 1}}$

The sum of n terms of a G.P. with first term a and common ratio r, when r = 1, is given by:

1. $S_n = \dfrac{a(1-r^n)}{1-r}$

2. $S_n = \dfrac{a(r^n-1)}{r-1}$

3. n²a

4. na

The sum of n terms of a G.P. with first term a and common ratio r, when r > 1, is :

1. $\dfrac{ar^n-1}{r-1}$

2. $\dfrac{1-ar^n}{1-r}$

3. $\dfrac{a(r^n-1)}{r-1}$

4. $\dfrac{a(1-r^n)}{1-r}$