Write first four terms of AP, When the first term a and the common difference d are given as follows:
i) a = 10, d = 10
ii) a = - 2, d = 0
iii) a = 4, d = - 3
iv) a = - 1, d = 1/2
v) a = - 1.25, d = - 0.25

Solution:

The general form of an arithmetic progression is a, (a + d), (a + 2d), (a + 3d),… where a is the first term and d is a common difference.

i) a = 10, d = 10

First term, a = 10

Second term, a + d = 10 + 10 = 20

Third term, a + 2d = 10 + 20 = 30

Fourth term, a + 3d = 10 + 30 = 40

The first four terms of the AP are 10, 20, 30, and 40.

ii) a = -2, d = 0

First term, a = - 2

Second term, a + d = - 2 + 0 = - 2

Third term, a + 2d = - 2 + 0 = - 2

Fourth term, a + 3d = - 2 + 0 = - 2

The first four terms of the AP are - 2, - 2, - 2, and -2.

iii) a = 4, d = - 3

First term, a = 4

Second term, a + d = 4 + (- 3) = 1

Third term, a + 2d = 4 + 2(- 3) = 4 - 6 = - 2

Fourth term, a + 3d = 4 + 3(- 3) = 4 - 9 = - 5

The first four terms of the AP are 4, 1, - 2, - 5.

iv) a = - 1, d = 1/2

First term, a = - 1

Second term, a + d = - 1 + 1/2 = - 1/2

Third term, a + 2d = - 1 + 2(1/2) = - 1 + 1 = 0

Fourth term, a + 3d = - 1 + 3(1/2) = - 1 + 3/2 = 1/2

The first four terms of the AP are - 1, - 1/2, 0, 1/2

v) a = - 1.25, d = - 0.25

First term, a = - 1.25

Second term, a + d = -1.25 + (-0.25) = - 1.25 - 0.25 = - 1.5

Third term, a + 2d = - 1.25 + 2 (- 0.25) = - 1.25 - 0.50 = - 1.75

Fourth term, a + 3d = - 1.25 + 3 (-0.25) = - 1.25 - 0.75 = - 2

The first four terms of the AP are - 1.25, - 1.5, - 1.75, and - 2.

☛ Check: NCERT Solutions Class 10 Maths Chapter 5

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Video Solution:

Write first four terms of AP, when the first term a and the common difference d are given as follows: i) a = 10, d = 10 ii) a = - 2, d = 0 iii) a = 4, d = - 3 iv) a = - 1, d = 1/2 v) a = - 1. 25, d = - 0.25

NCERT Solutions Class 10 Maths Chapter 5 Exercise 5.1 Question 2

Summary:

The first four terms of AP, when the first term a and the common difference d are given are as follows: i) a = 10, d = 10; 10, 20, 30 and 40 ii) a = - 2, d = 0; −2, −2, −2 and − 2 iii) a = 4, d = - 3; 4, 1, −2 and −5 iv) a = - 1, d = 1/2; −1, −1/2, 0 and 1/2 v) a = - 1.25, d = - 0.25; −1.25, −1.5, −1.75, and −2.

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