The sum of `1+2/5+3/5^2+4/5^3+....`upto n terms

Find the sum : 3.1^2+4.2^2+5.3^2+.... upto n terms.

Find the sum of 2.3+3.4+4.5+......to n terms.

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

1^(2) + 3^(2) + 5^(2) + …. upto n terms =

Find the sum of the series 1+3x+5x^2+7x^3+.......... upto n terms.

Find the sum of the series 1+3x+5x^(2)+7x^(3)+...... upto n terms.

Find the sum of the series 1+3x+5x^2+7x^3+.......... upto n terms.

The sum of the series 1+4+3+6+5+8+ upto n term when n is an even number (n^2+n)/4 2. (n^2+3n)/2 3. (n^2+1)/4 4. (n(n-1))/4 (n^2+3n)/4