find sum of `1+3x+6x^2+10x^3+15x^4 + -------oo` where ` |x| < 1 , x!= 0`

If the sum of 1 + 4x + 7x^(2) + 10x^(3) + ….oo (|x|lt 1) is (35)/(16) then x=

Find the sum to infinity of the series 1-3x+ 5x^(2)+7x^(3)+ cdots oo when |x| lt 1 .

1+3x+6x^(2)+10x^(3)+.oo, where (x=(1)/(3)) is

If the sum to infinty of the series , 1+4x+7x^(2)+10x^(3)+…. , is (35)/(16) , where |x| lt 1 , then 'x' equals to

If the sum to infinty of the series , 1+4x+7x^(2)+10x^(3)+…. , is (35)/(16) , where |x| lt 1 , then 'x' equals to

If the sum to infinty of the series , 1+4x+7x^(2)+10x^(3)+…. , is (35)/(16) , where |x| lt 1 , then 'x' equals to

The sum of the series 1 + 2x + 3x^(2) + 4x^(3) +"…." to oo where x lies between 0 and 1 i.e., 0 lt x lt 1 is :

Find the coefficient of x^7 in the expansion of (1+2x + 3x^2 + 4x^3 + 5x^4 + 6x^5 + 7x^6 + 8x^7)^10

The coefficient of x^(24) in the expansion of (1+3x+6x^(2)+10x^(3)+----+oo)^((2)/(3))=