.
The sum of r terms of an AP is 2r^2+3r.The nth term is
a. 2n- 1
b. 4n+1
c. 3n-1
d. 3n+ 1
Answers
Answered by
4
Answer:
6r−1
Step-by-step explanation:
MATHS
ANSWER
⇒S
1
=2(1)+3(1)
2
=5
S
n
=
2
n
{2a+(n−1)d}
S
n
=
2
n
{a+a+(n−1)d}
S
n
=
2
n
{a+a
n
}
2n+3n
2
=
2
n
{5+a
n
}
4+6n=5+a
n
⇒a
n
=6n−1
⇒a
r
=6r−1
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