Question

Write the formula to find the sum of first n terms of an AP if last term is not given

Answer 1

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Step-by-step explanation:

sum of n terms of any AP= (n÷2)×[2a(n-1)d]

here,

n= no.of terms

a=first term of an AP

d=common difference

Answer 2

Step-by-step explanation:

HELLO MATE

IN AN AP OF N TERMS

Sn= n/2(2a+(n-1)d)

HOPE IT HELPS