integration help (1 Viewer)

100percent

Member
Joined
Oct 28, 2004
Messages
148
Gender
Undisclosed
HSC
2005
how do you integrate
2x - 3
-------------- dx
x² - 2x + 2

with boundaries 2 & 1. thanks.

btw question is from cambridge page 155 question 17
 

shafqat

Member
Joined
Aug 20, 2003
Messages
517
Gender
Undisclosed
HSC
N/A
100percent said:
how do you integrate
2x - 3
-------------- dx
x² - 2x + 2

with boundaries 2 & 1. thanks.

btw question is from cambridge page 155 question 17
= 2x-2 / x² - 2x + 2 - 1/x² - 2x + 2
= 2x-2 / x² - 2x + 2 - 1/(x-1)^2 + 1
= log (x² - 2x + 2) - tan^-1(x-1)

edit: from 1 to 2, ah couldnt be bothered, i think you can do it yourself
 

100percent

Member
Joined
Oct 28, 2004
Messages
148
Gender
Undisclosed
HSC
2005
it never occured to me to split the 2x - 3 to 2x - 2 -1.
thanks man
 

..:''ooo

Member
Joined
Apr 5, 2005
Messages
68
Gender
Male
HSC
2005
100percent i think u need a treatment of corroneous integration questions
 

KFunk

Psychic refugee
Joined
Sep 19, 2004
Messages
3,323
Location
Sydney
Gender
Male
HSC
2005
I've been doing that coroneous revision set of 100 questions. It's a hell of a lot of integration.
 
Joined
Mar 26, 2004
Messages
154
Gender
Male
HSC
2005
uh from memory, I think u can change the (2^x)^1/2 to 2^(x/2) and then change the 2 to a e^ln2.
So u now have integral of e^((0.5x)ln2)dx which with a bit of trickery you can do.
Could be wrong but I think that's how you do it.
 

KFunk

Psychic refugee
Joined
Sep 19, 2004
Messages
3,323
Location
Sydney
Gender
Male
HSC
2005
I think that's pretty much it.

&int; 2<sup>x/2</sup> dx

convert it to base e to make your life less difficult ---->
e<sup>u</sup> = 2
log<sub>e</sub>2=u
hence 2 = e<sup>ln2</sup>

&int; 2<sup>x/2</sup> dx
= &int; (e<sup>ln2</sup>)<sup>x/2</sup> dx
= &int; e<sup>(x.ln2)/2</sup> dx
= (2/ln2) &int; ln2/2.e<sup>(x.ln2)/2</sup> dx
= (2/ln2).e<sup>(x.ln2)/2</sup> + C
= (2/ln2)&radic;(2<sup>x</sup>) + C
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top