# NCERT Class 11 Mathematics Solutions: Chapter 9 –Sequences and Series Miscellaneous Exercise 9 Part 1

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1. Show that the sum of terms of an A.P. is equal to twice the term.

Answer:

Consider be the first term and the common difference of the A.P. respectively.

It is known that the kth term of an A. P. is given by

So, the sum of terms of an A.P. is equal to twice the term.

2. If the sum of three numbers in A.P., is and their product is , find the numbers.

Answer:

Consider the three numbers in A.P. be .

According to the given information,

… (1)

… (2)

So, when , the numbers are and when ,

The numbers are .

So, the three numbers are .