Download the app

Questions  

 If a1,a2,a3,an are in H.P then a1a2+a2a3+a3a4++an1an=

Remember concepts with our Masterclasses.

80k Users
60 mins Expert Faculty Ask Questions
a
n−1a1an
b
n+1a1an
c
n−2a1an
d
n+4a1an

Ready to Test Your Skills?

Check Your Performance Today with our Free Mock Tests used by Toppers!

detailed solution

Correct option is A

1a1,1a2,1a3.....1anare in AP∴1a2−1a1=1a3-1a2=…=1an-1an−1=d⇒a1−a2a1a2=a2−a2a2a3=…⋅=an−1−anan−1an=d⇒a1−a2+a2−a3+…..+an−1−ana1a2+a2a3+…+an−1an=d ⇒a1a2+a2a3+.....+an-1an=a1-and                                           =n-1da1and                                           =n-1a1an


Similar Questions

Given that α,γ are roots of the equation Ax24x+1=0,  and β,δ the roots of the equation of Bx26x+1=0,  such that α,β,γ,  and δ  are in H.P., then


whats app icon
phone icon