The sum of first ‘n’ terms of an arithemetic progression is given by the formula
Sn
= 3n2 + n, then its 3rd term is
Answers
Answered by
9
Step-by-step explanation:
GiVEN
- Sum of first nth term of AP = 3n² + n
TO FiND
- The term 3rd term
SOLUTiON
- 1st term = 3*(1)² + 1
- 1st term = 4
- 2nd term = 3*(2)² + 2 - 4
- 2nd term = 14 - 4
- 2nd term = 10
- 3rd term = 3*(3)² + 3 - 14
- 3rd term = 30 - 14
- 3rd term = 16
Thus , the 3rd term is 16.
Answered by
2
We know that,
↝ Sum of n terms of an arithmetic sequence is,
Wʜᴇʀᴇ,
Sₙ is the sum of n terms of AP.
a is the first term of the sequence.
n is the no. of terms.
d is the common difference.
Now,
According to statement,
So,
On cancelation of n on both sides,
On comparing with sides,
and
Now,
Wᴇ ᴋɴᴏᴡ ᴛʜᴀᴛ,
↝ nᵗʰ term of an arithmetic sequence is,
Wʜᴇʀᴇ,
- aₙ is the nᵗʰ term.
- a is the first term of the sequence.
- n is the no. of terms.
- d is the common difference.
Tʜᴜs,
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