Question

For the following APs, write the first term and the common difference:
(i) 3,1,-1, -3,...
(ii) - 5, - 1, 3, 7. ...
(iii)1/3, 5/3, 9/3 ,13/3,....
(iv) 0.6, 1.7, 2.8, 3.9,...
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Answer 1

Answer:

(i) First term = 3, Common differpence = -2

(ii) First term = -5, Common difference = 4

(iii) First term = 1/3, Common difference = 4/3

(iv) First term = 0.6, Common difference = 1.1

Step-by-step explanation:

For an AP,

First term (a) = a1

Common difference (d) = [ (n)th term ] - [ (n-1)th term ] = an - a(n-1)

(i) AP :  3, 1, -1, -3,…….

  First term = a = 3

  Common difference = d = a2 - a(2-1) = a2 - a1 = 1 - 3 = -2

(ii) AP :  -5, -1, 3, 7,…….

  First term = a = -5

  Common difference = d = a2 - a(2-1) = a2 - a1 = (-1) - (-5) = -1 + 5 = 4

(iii) AP :  1/3, 5/3, 9/3 ,13/3,……..

  First term = a = 1/3

  Common difference = d = a2 - a(2-1) = a2 - a1 = 5/3 - 1/3 = (5-1)/3 = 4/3

(iv) AP :  0.6, 1.7, 2.8, 3.9,……..

  First term = a = 0.6

  Common difference = d = a2 - a(2-1) = a2 - a1 = 1.7 - 0.6 = 1.1

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