2.1+5+12+22+35+..." to "n" terms "

If 1+ 5+ 12+ 22 + 35+ ….. + to n terms = ( n^(2) (n+1) )/(2) then n^( th) term of L.H.S is

2+8+19+35+.... to n terms =

Find the sum of 1 + 5 + 12 + 22 + 35 +….upto n term.

Prove the following by the method of induction for all n in N : 1.3 + 3.5 + 5.7 +... to n terms =n/3 (4n^2 + 6n - 1) .

Find the sum of the following series : 1+5+12+22+35+…. to n terms.

Find the sum of the following series : 1.3+3.5+5.7+ .... to n terms .

Find S_n , if S_n = 1.3 + 2.4 + 3.5 + … upto n terms.

If (1 + 2 + 3 + 4 + 5 +………..upto n terms) / ( 1xx2 + 2xx3 + 3xx4 + 4xx5 + …. upto n terms) = 3/22 Find the value of n

If S_(n)=(1.2)/(3!)+(2.2^(2))/(4!)+(3.2^(3))/(5!)+... upto n terms then the sum infinite terms is

if (3 +5+7+9+…. " up to 35 terms " )/(5+8+11+ …. " up to n terms ")=7 , find the value of n.