Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 11

# If the Sum of N Terms of an A.P. Be 3 N2 − N and Its Common Difference is 6, Then Its First Term is - Mathematics

MCQ

If the sum of n terms of an A.P. be 3 n2 − n and its common difference is 6, then its first term is

• 2

• 3

• 1

• 4

#### Solution

2

$S_n = 3 n^2 - n$

$\Rightarrow S_1 = 3 \left( 1 \right)^2 - 1$

$\Rightarrow S_1 = 2$

$\therefore a_1 = 2$

Is there an error in this question or solution?

#### APPEARS IN

RD Sharma Class 11 Mathematics Textbook
Chapter 19 Arithmetic Progression
Q 3 | Page 51