HSC 2012-14 MX2 Integration Marathon (archive) (1 Viewer)

[dunjaaa]

Re: MX2 Integration Marathon

well when you manipulate dtheta in terms of dt that requires deriving inverse tan

 

[anomalousdecay]

Re: MX2 Integration Marathon

well when you manipulate dtheta in terms of dt that requires deriving inverse tan

You can do it a different way:




That avoids all the hassle.

 

[Sy123]

Re: MX2 Integration Marathon

well when you manipulate dtheta in terms of dt that requires deriving inverse tan

You aiming for state rank right?

Easy:



Harder: (includes series)





Another one:

 

[dunjaaa]

Re: MX2 Integration Marathon

oh ya u can just flip the derivative* LOL silly me strong derp/10

 

[dunjaaa]

Re: MX2 Integration Marathon

I'll give it a go but i just learnt integration na no where near as good as you to get state rank

 

[anomalousdecay]

Re: MX2 Integration Marathon

I'll give it a go but i just learnt integration na no where near as good as you to get state rank

Don't worry it takes time.


Just believe in yourself and you can possibly do it!!!

 

[HeroicPandas]

Re: MX2 Integration Marathon

Wait doesn't it become:



?

dang it lol

 

[anomalousdecay]

Re: MX2 Integration Marathon

dang it lol

Oh well. I guess we are all off at some stage.

Like today with the other question I tried to do. I forgot to use one identity and then did the question in the longest possible way, still getting it wrong.

Its been 3 months since we last did maths haha.

 

[Sy123]

Re: MX2 Integration Marathon

I'll give it a go but i just learnt integration na no where near as good as you to get state rank

Well still have the goal in your mind and go for it I reckon

Dw those integrals aren't actually hard in the "intuitive" sense.

 

[rumbleroar]

Re: MX2 Integration Marathon

Correct. Have a go at the one Sy posted before that I tried three times but didn't use the correct method for on the previous page.

I'm not sure if RR knows what to do (just ask for help).

Ah lol I got stuck during the thing, sorry I died lol. I think I just frustrated when I started, I think my dtheta was wrong so it stuffed the thing up. Are there solutions?

edit: got ln(2)

 

[anomalousdecay]

Re: MX2 Integration Marathon

Ah lol I got stuck during the thing, sorry I died lol. I think I just frustrated when I started, I think my dtheta was wrong so it stuffed the thing up. Are there solutions?

I can post up the full one if you like.

Do you want it now or do you want to have another go first?

 

[anomalousdecay]

Re: MX2 Integration Marathon

Ah lol I got stuck during the thing, sorry I died lol. I think I just frustrated when I started, I think my dtheta was wrong so it stuffed the thing up. Are there solutions?

edit: got ln(2)

Correct

Another one?

 

[rumbleroar]

Re: MX2 Integration Marathon



These are my solutions...they're really messy but if there's anything that would make them better, please let me know I need to work on correcting my working out because it's a bit incomprehensible at times

 

[Carrotsticks]

Re: MX2 Integration Marathon

View attachment 29859

These are my solutions...they're really messy but if there's anything that would make them better, please let me know I need to work on correcting my working out because it's a bit incomprehensible at times

You forgot to change your limits according to the variable you are integrating with respect to. Should be 1 to 0, not pi/2 to 0.

 

[rumbleroar]

Re: MX2 Integration Marathon

You forgot to change your limits according to the variable you are integrating with respect to. Should be 1 to 0, not pi/2 to 0.

aw crap, thanks carrot

also, where did the 4U marathon thread go?

 

[Carrotsticks]

Re: MX2 Integration Marathon

Here: http://community.boredofstudies.org/14/mathematics-extension-2/294872/hsc-2014-4u-marathon.html

 

[anomalousdecay]

Re: MX2 Integration Marathon

View attachment 29859

These are my solutions...they're really messy but if there's anything that would make them better, please let me know I need to work on correcting my working out because it's a bit incomprehensible at times

Its fine.

You can do it in less working out. My writing is 2-3 times bigger but I wouldn't do as many re-arranging steps. However, you do risk making a mistake with less steps.

Like to show the derivative it would take me 3 lines, and doing the rest of the question would take me 5 lines.

Change the limits first it is safer that way than substituting them in later (to me it was but it depends for you). I think that is the reason why you got stuck there.

 

[rumbleroar]

Re: MX2 Integration Marathon

Its fine.

You can do it in less working out. My writing is 2-3 times bigger but I wouldn't do as many re-arranging steps. However, you do risk making a mistake with less steps.

Like to show the derivative it would take me 3 lines, and doing the rest of the question would take me 5 lines.

Change the limits first it is safer that way than substituting them in later (to me it was but it depends for you). I think that is the reason why you got stuck there.

Nah, I didn't show you my previous working but I got stuck because I couldn't simplify the t-formula bit well enough because I forgot sec^2 = tan^2+1 (noob lol)

 

[anomalousdecay]

Re: MX2 Integration Marathon

Nah, I didn't show you my previous working but I got stuck because I couldn't simplify the t-formula bit well enough because I forgot sec^2 = tan^2+1 (noob lol)

I made that mistake once while doing Terry Lee, and then never forgot it since.

Hopefully you don't forget it now.

 

[rumbleroar]

Re: MX2 Integration Marathon

Need help with integrating this:

from 0 to 1, integral of (1+x)^1/2/(3+x)^1/2 (the entire fraction is rooted)

I attempted to use substitution of let u = rt (x+3)