(2x)/(1+(1)/(1+(x)/(1-x)))=1

The expression (1)/(1+(x)/(1-(x)/(x+2)))-:((1)/(1-x)+(1)/(1+x))/((1)/(1-x)-(1)/(1+x))

The expressin (1)/(1+(x)/(1-(x)/(x+2)))div ((1)/(1-x)+(1)/(1+x))/((1)/(1-x)-(1)/(1+x))

The expression (1)/(1+(x)/(1-(x)/(x+2)))div ((1)/(1-x)+(1)/(1+x))/((1)/(1-x)-(1)/(1+x)) (a) (2x)/(x^(2)+2x+2) (b) (2x)/(x^(2)-1) (c) 1 (d) x^(2)-1

If (1+x)(1+2x)(1+3x)((1+x)(1+2x)(1+3x))/((1-x)(1-2x)(1-3x))=K+(A)/(1-x)+(B)/(1-2x)+(C)/(1-3x) Then which of the following is correct?

Coefficient of x^(n) in ((1+x)(1+2x)(1+3x))/((1-x)(1-2x)(1-3x)) is

Sum to n terms of the series (1)/((1+x)(1+2x))+(1)/((1+2x)(1+3x))+(1)/((1+3x)(1+4x))+ ………

Sum to n terms of the series (1)/((1+x)(1+2x))+(1)/((1+2x)(1+3x))+(1)/((1+3x)(1+4x))+ is (i) (1+x)(1+nx)((1+x)(1+nx))/((1+x)(1+(n-1)x))( iv )((1+x)(1+(n+1)x))/((1+x)(1+(n+1)x))