Question

The A.P. whose sum of n terms is
2n2 + n is given by​

Answer 1

Answer:

AP is 3,7,11,15....

Step-by-step explanation:

Sn=

${2n}^{2} + n$

let n=1

Sum of first 1 term = 2+1 = 3 -eq 1

Sum of first 2 terms = 8+2=10. -eq 2

we know,

first term of an AP is a

Second term is a+d

a=3. (from eq 1)

(a)+(a+d)= 10

2a+d=10

2(3) +d=10

d=10-6

d=4

so we get a=3 , d=4

AP is 3,7,11,15....

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