Question

Find the sum of n terms of series 4 - 1 / n + 4 - 2 / n + 4 - 3 / n + . . . . . .

Answer 1

Sum of 4-1/n, 4-2/n, 4-3/n up to the nth term 

= (4 + 4 + 4 + 4 + 4 + ......... upto n terms) + (-1/n - 2/n - 3/n - ..........upto n terms)

= 4 ( 1+1+1+1.......... upto n terms) - 1/n (1 + 2 + 3 +4 .........upto n terms)

= 4 n - 1/n × n(n +1)/2

= 4n - (n+1)/2 

=  [ 8n - (n+1) ] / 2     .......taking L.C.M 

=( 7n - 1) / 2 Answer 

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Answer 2

hope it will hlp you