The sum of first n of …
CBSE, JEE, NEET, CUET
Question Bank, Mock Tests, Exam Papers
NCERT Solutions, Sample Papers, Notes, Videos
Posted by Ayush Jaiswal 6 years, 11 months ago
- 2 answers
Test
Related Questions
Posted by Sahil Sahil 1 year, 4 months ago
- 2 answers
Posted by Lakshay Kumar 1 year, 1 month ago
- 0 answers
Posted by Kanika . 1 month ago
- 1 answers
Posted by Parinith Gowda Ms 3 months, 2 weeks ago
- 0 answers
Posted by Vanshika Bhatnagar 1 year, 4 months ago
- 2 answers
Posted by Hari Anand 6 months, 1 week ago
- 0 answers
Posted by Parinith Gowda Ms 3 months, 2 weeks ago
- 1 answers
myCBSEguide
Trusted by 1 Crore+ Students
Test Generator
Create papers online. It's FREE.
CUET Mock Tests
75,000+ questions to practice only on myCBSEguide app
Gaurav Seth 6 years, 11 months ago
There is a mistake in a question.
I think question is like this
Question:
The sum of first n terms of an AP is given by Sn = 2n² + 3n . Find the sixteenth term of
the AP.
Solution:
Let an be the nth term & Sn be the sum of first n terms.
Given:
Sn = 2n²+3n
an = S(n) - S(n-1)
=2n²+3n -[ 2(n-1)²+3(n-1)]
= 2n²+3n -[2(n²+1-2n)+3n -3]
= 2n²+3n -[2n²+2-4n + 3n -3]
= 2n²+3n -2n²+4n-3n -2+3
= 2n²+2n²+3n -3n +4n -2+3
= 4n +1
an = 4n+1
a16= 4×16 +1= 64+1= 65
Hence, the 16th term of an AP is 65
1Thank You