• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

Answer to q10 f? (1 Viewer)

Joined
Sep 21, 2008
Messages
30
Gender
Male
HSC
2010
the answer is 41/12 -2ln2
I think you stuffed up the substitution of 0, instead of 1 you got -1 so hence you ended up with 41/2 - 2ln2

A = Integral of x - x^2 /2 + x^3/3 - ln(1+x) from 0 to 1

= {[x^2 /2 - x^3/6 + x^4/12] - [(1+x)ln(1+x) - (1+x)]} from 0 to 1

= {[1/2 - 1/6 + 1/12)] - [2ln(2) - 2]} - {[0] - [(1ln(1) - 1)]}

= { 5/12 - 2ln(2) + 2 } - {0-[0-1]}

= 29/12 - 2ln(2) - {0--1}

= 29/12 - 2ln(2) - 1

= 17/12 - 2ln(2)
 

boxhunter91

Member
Joined
Nov 16, 2007
Messages
736
Gender
Male
HSC
2009
Woot i did everything write except i used the x^3/(1+x) integral lol.
I got an answer of 2 ln 2 rekn ill get the 1 mark?
 

gunne

Mew Nember
Joined
Mar 25, 2008
Messages
33
Gender
Male
HSC
2009
i screwed up the very simple derivation... at the beginning of q10
hopefully ecf!
 

daniieee

Member
Joined
Aug 12, 2009
Messages
115
Location
Sydney
Gender
Female
HSC
2009
I think you stuffed up the substitution of 0, instead of 1 you got -1 so hence you ended up with 41/2 - 2ln2

A = Integral of x - x^2 /2 + x^3/3 - ln(1+x) from 0 to 1

= {[x^2 /2 - x^3/6 + x^4/12] - [(1+x)ln(1+x) - (1+x)]} from 0 to 1

= {[1/2 - 1/6 + 1/12)] - [2ln(2) - 2]} - {[0] - [(1ln(1) - 1)]}


= { 5/12 - 2ln(2) + 2 } - {0-[0-1]}

= 29/12 - 2ln(2) - {0--1}

= 29/12 - 2ln(2) - 1

= 17/12 - 2ln(2)
Got to about here, and then PENS DOWN! !#%^!!@%&#!%#@$%! Stupidly wasted too much time fixing up 9b.
 

heavenfalling

New Member
Joined
Jun 30, 2009
Messages
11
Gender
Undisclosed
HSC
2009
I stuffed up part d (the graphs) but still managed to do it. I got something along those lines. Lol 10 e & f is easier compared to other questions.
 

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

Top