The marginal cost of producing the Xth role of film is given by 5+1/(X+1)^2. The total cost to produce one roll is $1000. find the total cost function.

to take the antiderivative of 5+1/(X+1)^2 I replaced X+1 with R and wrote

(5+1)(R^-2). I took the antiderivative of this :

(5+1)(R^-1)/-1

I replaced R with X+1 :

(5+1)/(X+1)

What am I doing wrong?