Math miscellaneousHard
Question
If a1, a2, .... , an are in H.P., then the expression a1a2 + a2a3 + .... + an-1an is equal to
Options
A.n(a1 - an)
B.(n - 1) (a1 - an)
C.na1an
D.(n - 1)na1an
Solution
= d (say)Then a1a2 =
, a2a3 = 
, ....., an-1an = 
∴ a1a2 + a2a3 + .... an-1an =
Also, 
+ (n - 1)d ⇒
= (n - 1)a1anCreate a free account to view solution
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