# For the following APs,

Question.

For the following APs, write the first term and the common difference :

(i) $3,1,-1,-3, \ldots$

(ii) $-5,-1,3,7, \ldots \ldots$

(iii) $\frac{1}{3}, \frac{5}{3}, \frac{9}{3}, \frac{13}{3}, \ldots$

(iv) $0.6,1.7,2.8,3.9, \ldots$

Solution:

(i) $\mathrm{a}=3, \mathrm{~d}=\mathrm{t}_{2}-\mathrm{t}_{1}=1-3=-2$,

i.e., $d=-2$

(ii) $a=-5, d=4$

(iii) $a=\frac{1}{3}$

$\mathrm{d}=\mathrm{t}_{2}-\mathrm{t}_{1}=\frac{5}{3}-\frac{1}{3}=\frac{4}{3}$

(iv) $0.6,1.7,2.8,3.9 \ldots$

$a=0.6$

$\mathrm{d}=\mathrm{t}_{2}-\mathrm{t}_{1}$

$=1.7-0.6$

$=1.1$