If first term is 1 , then find the sum of first 30 terms.

Asked by sunil_0010 | 1st Jul, 2009, 10:19: PM

Expert Answer:

the sum of first 20 terms of an A.P.

with first term as a and common diff as d is



 sum of the next 20 terms

=sum of the first 40 terms -sum of the first 20 terms

=40/2[2a+39d]-   20/2[2a+19d]


acc to qn


solving we get


is it given that first term is1?

then d=2

then you can find the sum of the first thirty terms using formula for sum of n terms.

Answered by  | 1st Jul, 2009, 10:47: PM

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