ATAR Notes: Forum

VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: monokekie on July 09, 2009, 01:54:55 pm

Title: Qs (pls help)
Post by: monokekie on July 09, 2009, 01:54:55 pm: [IMG]http://img268.imageshack.us/img268/9792/ch11exq9.png[/img]
(source:cambridge essential)
tkx!
Title: Re: Qs (pls help)
Post by: Damo17 on July 09, 2009, 02:51:12 pm: Quote from: monokekie on July 09, 2009, 01:54:55 pm
[IMG]http://img268.imageshack.us/img268/9792/ch11exq9.png[/img]
(source:cambridge essential)
tkx!

part d)
from part c: $p= \frac{1}{9(\frac{2}{3})^t+1}$

for $p>\frac{1}{2}$

$\frac{1}{2}< \frac{1}{9(\frac{2}{3})^t+1}$

$\frac{1}{2} (9(\frac{2}{3})^t+1) <1$

$9(\frac{2}{3})^t+1<2$

$(\frac{2}{3})^t < \frac{1}{9}$

$t > \frac{log_e (\frac{1}{9})}{log_e(\frac{2}{3})}$

$t> 5.42$

EDIT: changed the inequality signs for all except last two lines. Got a bit mixed up, sorry.
Title: Re: Qs (pls help)
Post by: monokekie on July 09, 2009, 02:55:10 pm: ^^^

thanks Damo17! Your solution 's better than the cambridge solution(which i couldn't understand):)
Title: Re: Qs (pls help)
Post by: d0minicz on July 09, 2009, 03:09:00 pm: lol are those the exercise solutions in pdf form?
Title: Re: Qs (pls help)
Post by: monokekie on July 09, 2009, 03:10:48 pm: um, nope. They are in hard copy, for chapter reviews :)
Quote from: d0minicz on July 09, 2009, 03:09:00 pm
lol are those the exercise solutions in pdf form?
Title: Re: Qs (pls help)
Post by: Damo17 on July 09, 2009, 03:13:52 pm: I made a mistake with the inequality signs, post edited.
Title: Re: Qs (pls help)
Post by: monokekie on July 09, 2009, 03:14:34 pm: Quote from: Damo17 on July 09, 2009, 03:13:52 pm
I made a mistake with the inequality signs, post edited.

yeah i understood that lol, tkx