then the expression
As we learnt in
Harmonic Progression (HP) -
The sequence
Where for each is an HP, if the sequence
is an AP
- wherein
eg
If a1, a2,a3,--- are in A.P
Now
similarly a n-1 -a n=dan-1an
Now a1-a2=da1a2
a2-a3=da2a3
.............................
Add a1 - an = d(a1 a2 + a2 a3+ ..............an - 1 an) (i)
Now,
a1-an=(n-1)a1and (ii)
So from (i) & (ii) on comparison
so answer is (n-1)a1an
Option 1)
this is incorrect option
Option 2)
this is incorrect option
Option 3)
this is incorrect option
Option 4)
this is correct option
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