" (i) "1.2+2.3+3.4+..." to "n" terms "

Find the sum of the following series : 1.2+2.3+3.4+ .... to n terms .

Find sum of series 1.2+2.3+3.4.... upto n terms

1/(1.2)+1/(2.3)+1/(3.4)+... to n terms

If (1.2+2.3+3.4+cdots "to n terms")/(1+2+3+cdots "to n terms") =6 find n.

The value of the sum 1.2.3+2.3.4+3.4.5+… upto n terms is equal to

{:("If",a = 1 + 2 + 4 + ..."to n terms"),(,b = 1 + 3 + 9 + ..."to n terms"),(,c =1 + 5 + 25+ ..."to n terms"):} then |(a,2b,4c),(2,2,2),(2^(n),3^(n),5^(n))|=

{:("If",a = 1 + 2 + 4 + ..."to n terms"),(,b = 1 + 3 + 9 + ..."to n terms"),(,c =1 + 5 + 25+ ..."to n terms"):} then |(a,2b,4c),(2,2,2),(2^(n),3^(n),5^(n))|=

{:("If",a = 1 + 2 + 4 + ..."to n terms"),(,b = 1 + 3 + 9 + ..."to n terms"),(,c =1 + 5 + 25+ ..."to n terms"):} then |(a,2b,4c),(2,2,2),(2^(n),3^(n),5^(n))|=