Sum of n terms of A.P
Asked by ravikiran
| 11th Jul, 2009,
11:42: AM
Expert Answer:
s40={41,42,....80}
so sum of all terms in s40
=41+42+..+80
this is the sum of an A.P.
with 41 as the first term(a) and 1 as the common diff.(d) and there are total 40 terms(n)
so using the formula
sum of n terms
=n/2[a+l} where l is the last term
we get
reqd sum
=40/2[41+80]
=4840
Answered by
| 11th Jul, 2009,
03:49: PM
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