Find the `1+2.2+3.2^2+…….+t_n`

Find the sum 1+2.2+3.2^(2)+4.2^(3)+....+n.2^(n-1)

Find the sum of 1^1 n + 2^2 (n - 1) + 3^2 (n - 2) + 4^2 (n -3) ……upto 'n' terms.

Find the first five terms of the sequence for which t_1=1, t_2=2 and t_(n+2)=t_n+t_(n+1)

Let S_n=1/1^2 + 1/2^2 + 1/3^2 +….. + 1/n^2 and T_n=2 -1/n , then :

Let S_n=1/1^2 + 1/2^2 + 1/3^2 +….. + 1/n^2 and T_n=2 -1/n , then :

Find the first five terms of the sequence for which t_(1)=1,t_(2)=2 and t_(n+2)=t_(n)+t+(n+1)

If (1^2-t_1)+(2^2-t_2)+---+(n^2-t_n)=(n(n^2-1))/3 , then t_n is equal to a. n^2 b. 2n c. n^2-2n d. none of these

Find the sum to n terms of the series (1)/(1+1^(2)+1^(4))+(2)/(1+2^(2)+2^(4))+(3)/(1+3^(2)+3^(4))+ that means t_(r)=(r)/(r^(4)+r^(2)+1) find sum_(1)^(n)