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March 29, 2024, 05:37:37 am

Author Topic: 3U Maths Question Thread  (Read 1230348 times)  Share 

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conic curve

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Re: 3U Maths Question Thread
« Reply #360 on: July 23, 2016, 09:37:10 pm »
0





This is a completely different question

I already solved the previous question

This is the question now:

RuiAce

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Re: 3U Maths Question Thread
« Reply #361 on: July 23, 2016, 09:42:55 pm »
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Bit confused here. What do you mean by that expression on the LHS?

Or was the square root not meant to be there

conic curve

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Re: 3U Maths Question Thread
« Reply #362 on: July 23, 2016, 09:44:33 pm »
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Bit confused here. What do you mean by that expression on the LHS?

Or was the square root not meant to be there

whoops my bad sorry

Basically that question but without the squareroot value

Thanks

RuiAce

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Re: 3U Maths Question Thread
« Reply #363 on: July 23, 2016, 09:53:10 pm »
+1


Notes:

conic curve

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Re: 3U Maths Question Thread
« Reply #364 on: July 23, 2016, 09:56:51 pm »
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Notes:


Um, there was no restriction given on the question

Whenever I have a question with a restriction, I usually post it up and in this case I didn't hence there is no restriction

Next time I'll make it more clearer for you so then you don't do the wrong things

RuiAce

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Re: 3U Maths Question Thread
« Reply #365 on: July 23, 2016, 10:04:24 pm »
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conic curve

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Re: 3U Maths Question Thread
« Reply #366 on: July 23, 2016, 10:14:45 pm »
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I saw a solution to a similar question to this and this was how I ended up doing it:

RuiAce

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Re: 3U Maths Question Thread
« Reply #367 on: July 23, 2016, 10:19:46 pm »
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Lol fair enough.

But that solution lacks rigour in my eyes. Without proper justification that both alpha and beta lie between -pi/2 and pi/2, cancelling out the tan's is not properly justified.

(Or it could be I'm too used to uni maths and everything has to be presented with 100% precision)

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #368 on: July 24, 2016, 12:24:18 am »
+1
Lol fair enough.

But that solution lacks rigour in my eyes. Without proper justification that both alpha and beta lie between -pi/2 and pi/2, cancelling out the tan's is not properly justified.

(Or it could be I'm too used to uni maths and everything has to be presented with 100% precision)

I'd be leaning towards saying that the solution would probably be passable at this level of study, but I could be mistaken. The train of thought is solid enough  ;D that being said, I recommend getting in the habit of writing all restrictions in the HSC, even those which are seemingly inconsequential or even obvious, to make the marker happy and to make sure your reasoning is clear, catch tricks, etc etc  ;D you'd almost definitely get away with it, but better safe than sorry  :D

RuiAce

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Re: 3U Maths Question Thread
« Reply #369 on: July 24, 2016, 01:26:47 am »
+1
I'd be leaning towards saying that the solution would probably be passable at this level of study, but I could be mistaken. The train of thought is solid enough  ;D that being said, I recommend getting in the habit of writing all restrictions in the HSC, even those which are seemingly inconsequential or even obvious, to make the marker happy and to make sure your reasoning is clear, catch tricks, etc etc  ;D you'd almost definitely get away with it, but better safe than sorry  :D
It's as you said in the lecture

I'm the type of person who will get you out for anything in maths :P

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #370 on: July 24, 2016, 01:50:13 am »
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It's as you said in the lecture

I'm the type of person who will get you out for anything in maths :P

You keep me on my toes, that's for sure  ;)

dtinaa

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Re: 3U Maths Question Thread
« Reply #371 on: July 24, 2016, 02:48:53 pm »
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Hey everyone,

I found this hectic induction question but I couldn't find the solutions, if anyone can do it please reply!!!

Also the image was too big to attach so I just put it onto a document...



RuiAce

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Re: 3U Maths Question Thread
« Reply #372 on: July 24, 2016, 03:37:17 pm »
+1
Hey everyone,

I found this hectic induction question but I couldn't find the solutions, if anyone can do it please reply!!!

Also the image was too big to attach so I just put it onto a document...







Hence true by induction

alexander.chu1

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Re: 3U Maths Question Thread
« Reply #373 on: July 25, 2016, 06:16:54 pm »
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Hey guys this is my first time on here, I'm struggling with probability right now (mainly permutations and combinations). Could someone please help me with this question?

The letters of the word PRINTER are arranged in a row. Find the probability that: (a) the word starts with the letter E,
(b) the letters I and P are next to one another,
(c) there are three letters between N and T,
(d) there are at least three letters between N and T.
Hi Tim,
I think the answer are 1/7 , 2/7,1/7, and 2/7.
Please correct me if i am wrong thanks!

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #374 on: July 25, 2016, 07:38:03 pm »
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Hi Tim,
I think the answer are 1/7 , 2/7,1/7, and 2/7.
Please correct me if i am wrong thanks!

Hey Alex, welcome to the forums!!  ;D let me know if you need any help finding things!

Those answers match Rui and I's, you are correct indeed!  ;D