Problem - 4348
Show that $$\frac{1}{(1-x)^2} = 1 + 2x + 3x^2 + 4x^3 + \cdots$$
This relation can be directly derived by applying the conclusion of # 4284.
Alternatively, it can also be obtained by taking derivative on the both side of $$\frac{1}{1-x}=1+x+x^2 + x^3 +\cdots$$