How do you integrate (x-5)/(x-2)^2 using partial fractions?

1 Answer
Jul 29, 2016

int (x-5)/(x-2)^2 .d x=l n(|x-2|)-3/(x-2)+C

Explanation:

int (x-5)/(x-2)^2 .d x=?

"let us write (x-5) as (x-2-3)"

int (x-2-3)/(x-2)^2 * d x

"split (x-2-3 )

int cancel((x-2))/cancel((x-2)^2)* d x-int 3/(x-2)^2 *d x

int (d x)/(x-2)-3 int (d x)/(x-2)^2

"1- solve " int (d x)/(x-2)

"substitute u=x-2" ; "d u=d x

int (d x)/(x-2)=(d u)/u=l n u

"undo substitution "

int (d x)/(x-2)=l n (x-2)

"2- now solve "3 int (d x)/(x-2)^2

u=x-2" ; " d x=d u" ; "3 int (d u)/u^2=3int u^-2 d u

3int (d x)/(x-2)=1/(-2+1 )u^(-2+1)=-3*u^(-1)=-3/u

"undo substitution"

3int(d x)/(x-2)^2=-3/(x-2)

"The problem is solved:"

int (x-5)/(x-2)^2 .d x=l n(|x-2|)-3/(x-2)+C