The sum of the first 9 terms of an A.P is 81 and the sum of it's f | Filo
filo Logodropdown-logo

Class 10


All topics

Sequences and Series

view icon553
like icon150

The sum of the first terms of an is and the sum of it's first terms is Find the first term, the common difference and the sum upto term.

  1. None of these
Correct Answer: Option(d)
Solution: Sum of the term
Given sum of terms

Sum of terms

Multiply eq by and and eq by and subtract both the equation

Now substitute the in eq

Sum of the 15th Term


view icon553
like icon150
filo banner image

Connecting you to a tutor in 60 seconds.

Get answers to your doubts.

playstore logoplaystore logo
Similar Topics
introduction to trigonometry
some applications of trigonometry
quadratic equations
surface areas and volumes