find the sum of the series :1+3+4+8+7+13+10+18+........to 23 terms.
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Answered by
4
it has 2 ap's sum of first is 12/2(2( 1)+(11)3)
and second is ap of comm an diff. of 5
and second is ap of comm an diff. of 5
kamalprasad:
please elaborate
then what is no of terms on both cases
thank u ....i do it ..
Answered by
2
Hi Friend !!
Here is ur answer !!!
a = 1 , d = 3-1 = 2 , n = 23
Sn = n/2 (2a+(n-1)d)
= 23/2 (2+22(2))
= 23/2 (2+44)
= 23/2 (46)
= 23×23
= 529
Hope it helps u :-)
Here is ur answer !!!
a = 1 , d = 3-1 = 2 , n = 23
Sn = n/2 (2a+(n-1)d)
= 23/2 (2+22(2))
= 23/2 (2+44)
= 23/2 (46)
= 23×23
= 529
Hope it helps u :-)
but this series are not in A.P.after 8 their is 7.i cant understand
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