If a,a1,a2,a3,....,a2n,b are in AP and a,g1,g2,g3,....,g2n,b are in GP and h is the harmonic mean of a and b then a1+a2ng1g2n+a2+a2n−1g2g2n−1+....+an+an+1gngn+1 is equal to
A
2nh
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
2nh
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
nh
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
nh
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is D2nh a1+a2ng1g2n+a2+a2n−1g2g2n−1+........+an+an+1gngn+1=n(2a+2ndar2n)
We got above expression by substituting a1,a2,....a2n,g1,g2,....g2n values.
a1=a+d,a2=a+2d,......,a2n=a+(2n−1)d, where d is common ratio for AP.
g1=ar,g2=ar2,......,g2n=ar2n. where r is common ratio of GP