integration question (1 Viewer)

[Schniz]

got no idea!!!......

show that (x+7)/(x-1) can be written as 1 + [8/(x-1)] and hence show that then integral from 2 to (e+1) of (x+7)/(x-1) = (e+7)


thanks.

 

[pLuvia]

For (x+7)/(x-1) you have to use long division to get 1+8/(x-1)

∫{2-->(e+1)}[1+8/(x-1)]dx
=[x+8ln(x-1)]{2-->e+1]
=e+7

 

[alexvincent]

When I did 2u I was never required to know long division. I only learnt long division when I did the 3u course. Ask your teacher if long division is required knowledge as per the 2u syllabus.

In my experience with 2u, if you don't need to know something, make sure that you don't know it. Leave some brain power for some more valuable information.

 

[Riviet]

An alternative to long division, known as manipulation:

(x+7)/(x-1)=(x-1+8)/(x-1)

=(x-1)/(x-1) + 8/(x-1)

=1 + 8/(x-1)

 

[pLuvia]

An alternative to long division, known as manipulation:

(x+7)/(x-1)=(x-1+8)/(x-1)

=(x-1)/(x-1) + 8/(x-1)

=1 + 8/(x-1)

I don't think 2u learns that way, 4u have to as part of partial fractions though.

I'm pretty sure 2u learns the long division as it is in the 2u fitzpatrick book

 

[Riviet]

I was only offering it as an alternative... anyway, it's not very hard for a 2u student to do once you get the idea.