Question

32. The sum of first n terms of an arithmetic progression is 210 and sum of its first (n - 1) terms is 171. If
the first term 3, then write the arithmetic progression.​

Answer 1

Answer:

Arithmetic progression is 3,7,11,15... 39

Step-by-step explanation:

To find the AP if the sum of first n terms of arithmetic progression is 210 and sum of its first (n-1) terms is 171. If the first term is 3 .

As we know that if AP has n terms,then after removing (n-1) terms,we are left with the last term.

ACF, last term is 210-171

l= 39

a= 3

now as we know the AP has n terms so put the formula of n terms as shown under to find the value of d

common difference d= 4

so, arithmetic progression is 3,7,11,15... 39

Hope it helps you.

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