The Student Room Group
Reply 1
substitution? Ie, let u=x-1
u = x-1

du/dx = 1

dx = du

integral u^-2 du

= -u^-1
= -(x-1)^-1
Reply 3
Use the chain rule. Add one to the power, then divide the whole bracket by (the new power times by the dericitive of whats inside the bracket)....Thus giving you (x-1)^-1/-1
Reply 4
theflyingpig
u = x-1

du/dx = 1

dx = du

integral u^-2 du

= -u^-1
= -(x-1)^-1

You're right.
buj
How do you integrate brackets.

For example, (x-1)^-2

any help appreciated.


If you don't want to use substitution, add one to the power to give (x1)1 (x-1)^{-1} . If you then differentiate back again, you get (x1)2 - (x-1)^{-2} , which is -1 times too big. We therefore need to divide what we differentiated by -1, giving the answer as (x1)1 -(x-1)^{-1} .
Reply 6
0129Hippy
You're wrong.


Nope you need to revise. -2 + 1 does not equal -3
0129Hippy
You're wrong.

No he's right.
Reply 8
Ooooopsies...I apologise will all my heart.
Reply 9
First two people were wrong.

You get 1/(1-x)

By doing it the way Daniel Friedman explained.
Reply 10
buj
How do you integrate brackets.

For example, (x-1)^-2

any help appreciated.


you've left it quite late :eek:

past papers are your friends :smile:
Reply 11
uthred50
Actually, you're both wrong.

You get 1/(1-x)


No you're wrong lol

-(x-1)^-1 = 1/(1-x)
Reply 12
n1r4v
No you're wrong lol

-(x-1)^-1 = 1/(1-x)


i was refering to the other dude, but like 3 people posted before i put that post lol

The answer is definately 1/(1-x), whcih can also be phrased as (1-x)^-1
Reply 13
you can not integrate brackets....first of all you need to expand the braket... and then integrate.
medione
you can not integrate brackets....first of all you need to expand the braket... and then integrate.


You are wrong, unless you want to be forever integrating an infinite expansion....
Reply 15
medione
you can not integrate brackets....first of all you need to expand the braket... and then integrate.


Yes you can, substitution or chain rule.
Reply 16
If your revising for Edexcel Core 4 on Thursday you really should be able to do this by substitution or by observation by now.
we're all wrong. the answer is π\displaystyle \pi... :biggrin:
Reply 18
louiscbrooks
If your revising for Edexcel Core 4 on Thursday you really should be able to do this by substitution or by observation by now.


Do you have any more logic puzzles :p:
Reply 19
n1r4v
Do you have any more logic puzzles :p:

lol no

Latest