Help Please (1 Viewer)

[damo676767]

i am stuck with an intergration problem, its probably really simple but i cant figure it out. HAve a look and see if you can please

(2x + 3)/((x + 1)(x + 2))^2


Please help

 

[wanton-wonton]

Have you tried partial fractions?

let (2x + 3)/((x + 1)(x + 2))^2 = A/(x+1) + (Bx+C)/(x+2)^2.

That should be right, from memory.

 

[acmilan]

Wouldnt substituting u = x² + 3x + 2 work?

 

[wanton-wonton]

Oh, it was ALL squared. Sorry.

 

[Trefoil]

Partial fractions also works but you would need to make a small adjustment which is beyond the 4u course (refer to Coroneos if you are interested). In partial fractions, it would be:

(2x + 3)/((x + 1)(x + 2))^2 = A/(x+1)+B/(x+1)^2+C/(x+2)+D/(x+2)^2

This method is long and boring and the substitution is far superior, however it is good to know all methods available to you.

 

[adzy]

So answer is just -1/(x^2+3x+2) + c using acmilan's subsitution

 

[damo676767]

thanyou all very much

it works