Find the sum of the series: `1. n+2.(n-1)+3.(n-2)++(n-1). 2+n .1.`

Find the sum of the series 1xxn+2(n-1)+3xx(n-2)++(n-1)xx2+nxx1.

Find the sum of the series 1xxn+2(n-1)+3xx(n-2)++(n-1)xx2+nxx1.

Find the sum of the series 1xxn+2(n-1)+3xx(n-2)++(n-1)xx2+nxx1.

Find the sum of the series 1.n + 2 .(n-1) + 3.(n-2) + cdots + ( n-1) .2 + n.1.

Find the sum of the series 1xx n+2(n-1)+3xx(n-2)+...+(n-1)xx2+n xx1

Find the sum of the series 1*n+2*(n-1)+3*(n-2)+4*(n-3)+....(n−1).2+n.1"

Find the sum of the series 1*n+2*(n-1)+3*(n-2)+4*(n-3)+....(n−1).2+n.1" also, find the coefficient of x^(n-1) in th cxpansion of (1+2x+3x^(2)+"...."nx^(n-1))^(2) .

Find the sum of the series 1*n+2*(n-1)+3*(n-2)+4*(n-3)+"..."+(n-1)*2+n*1 also, find the coefficient of x^(n-1) in th cxpansion of (1+2x+3x^(2)+"...."nx^(n-1))^(2) .

Find the sum of the series 1*n+2*(n-1)+3*(n-2)+4*(n-3)+"..."+(n-1)*2+,*1 also, find the coefficient of x^(n-1) in th cxpansion of (1+2x+3x^(2)+"...."nx^(n-1))^(2) .

From the relation 1+x+x^(2)+* * * + x^(n-1)=(1-x^(n))/(1-x) , find the sum of the series 1+2x+3x^(2)+* * * +(n-1)x^(n-2) .