Match the AP’s given in column A with suitable common differences given in column B.
Column A | Column B | ||
(A1) | 2, - 2 – 6, - 10, … | (B1) |
|
(A2) | a = - 18, n = 10, an = 0 | (B2) | –5 |
(A3) | a = 0, a10 = 6 | (B3) | 4 |
(A4) | a2 = 13, a4 = 3 | (B4) | –4 |
(B5) | 2 | ||
(B6) |
| ||
(B7) | 5 |
(A1)
AP is 2, - 2, - 6, - 10, ….
So common difference is simply
a2 - a1 = - 2 - 2 = - 4 = (B3)
(A2)
Given
First term, a = - 18
No of terms, n = 10
Last term, an = 0
By using the nth term formula
an = a + (n - 1)d
0 = - 18 + (10 - 1)d
18 = 9d
d = 2 = (B5)
(A3)
Given
First term, a = 0
Tenth term, a10 = 6
By using the nth term formula
an = a + (n - 1)d
a10 = a + 9d
6 = 0 + 9d
= (B6)
(A4)
Let the first term be a and common difference be d
Given that
a2 = 13
a4 = 3
a2 - a4 = 10
a + d - (a + 3d) = 10
d - 3d = 10
- 2d = 10
d = - 5
= (B1)
2