Question

For the following APs, write the first term and the common difference:
(i) 3, 1, − 1, − 3 …
(ii) − 5, − 1, 3, 7 …
(iii) \(\frac{1}{3}, \frac{5}{3},\frac{9}{3},\frac{13}{3}\) ,…
(iv) 0.6, 1.7, 2.8, 3.9 …

Answer 1

(i) 3, 1, −1, −3 … 
Here, first term, a = 3 
Common difference, d = Second term − First term 
d = 1 − 3
d = −2

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(ii) −5, −1, 3, 7 …
Here, first term, a = −5
Common difference, d = Second term − First term
d = (−1) − (−5)
d = − 1 + 5
d = 4

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(iii) \(\frac{1}{3}, \frac{5}{3} , \frac{9}{3}, \frac{13}{3}\) ,…
Here, first term, a = \(\frac{1}{3}\)
Common difference, d = Second term − First term
\(\text{d}=\frac{5}{3} - \frac{1}{3}\)
\(\text{d} = \frac{4}{3}\)

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(iv) 0.6, 1.7, 2.8, 3.9 …
Here, first term, a = 0.6 
Common difference, d = Second term − First term
d = 1.7 − 0.6
d = 1.1