if n^th term of an AP is 1/3(2n+1), then find the sum of its 19 term
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to obtain common difference we need to do n2-n1=d
n2=5/3 and n1=1
now d =2/3
as we know sn=n/2 (2a+(n-1)d)
Where n=no. of terms
d common difference
sn sum of n terms of an ap
then s19=19/2 {2 (1)+(19-1)×(2/3)}
=19 (1+6)
=19×7=133
n2=5/3 and n1=1
now d =2/3
as we know sn=n/2 (2a+(n-1)d)
Where n=no. of terms
d common difference
sn sum of n terms of an ap
then s19=19/2 {2 (1)+(19-1)×(2/3)}
=19 (1+6)
=19×7=133
saloni2019sharma:
aise hi n=3,4,5,6...value dete hi hme ap mil jayegi
now common difference hota hai Tn-Tn-1
thank u very much
mujhe samjh aa gya
hmare pass 2nd or first term dono hai to 2nd term me se 1 term subtract krne pe hme common difference mil jayega
okkk fine
or correct answer kya hai??
correct answer is 133
so I obtained that
yaa
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