If a(1) , a(2), "……………" a(n) are in H.P....

If `a_(1) , a_(2), "……………" a_(n)` are in H.P., then the expression `a_(1) a_(2) + a_(2) a_(3)+"…….."+ a_(n-1) a_(n)` is equal to `:`

`n(a_(1)-a_(n))`

`(n-1)(a_(1)-a_(n))`

`n a_(1) a_(n)`

`(n-1) a_(1) a_(n)`

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