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March 28, 2024, 07:54:32 pm

Author Topic: 3U Maths Question Thread  (Read 1230143 times)  Share 

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RuiAce

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Re: 3U Maths Question Thread
« Reply #420 on: August 02, 2016, 01:43:52 pm »
+1
This is another attempt at Q2.



Edit: Posts merged
How do you do part iii, iv, and v   ???
I've noticed that a lot of your questions are projectile motion based. Is there anything about the topic that troubles you?

Most of the questions just require knowing what means what (e.g. time of flight means y=0) and braving heavy algebra.
« Last Edit: August 02, 2016, 01:48:19 pm by RuiAce »

massive

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Re: 3U Maths Question Thread
« Reply #421 on: August 02, 2016, 02:10:29 pm »
0
I've noticed that a lot of your questions are projectile motion based. Is there anything about the topic that troubles you?

Most of the questions just require knowing what means what (e.g. time of flight means y=0) and braving heavy algebra.

No I understand the main concepts. its just that rn im doing application of calculus to the physical world questions, and the ones im posting (like the one i just posted) are not the ordinary kind. For example, in the one i posted, i got the first two parts that were about projectile motion, but the last three parts are about the target moving, i just dont know how to do that

dreamdog10

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Re: 3U Maths Question Thread
« Reply #422 on: August 02, 2016, 02:26:44 pm »
0
Hi! So i was wondering when using Newton's method of approximation, whether i need my calculator in radians or degrees such as in the question attached :)
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jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #423 on: August 02, 2016, 02:29:52 pm »
+1
Hi! So i was wondering when using Newton's method of approximation, whether i need my calculator in radians or degrees such as in the question attached :)

Hey dream dog, radians!! Always radians unless you see the degree symbol (and you'll never see it when doing things with Calculus)  ;D

jakesilove

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Re: 3U Maths Question Thread
« Reply #424 on: August 02, 2016, 02:30:32 pm »
+1
Hi! So i was wondering when using Newton's method of approximation, whether i need my calculator in radians or degrees such as in the question attached :)

Hey! Unless you're working with angles which are specifically in degrees, you should ALWAYS be using radians.
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dreamdog10

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Re: 3U Maths Question Thread
« Reply #425 on: August 02, 2016, 02:34:57 pm »
+1
Hey! Unless you're working with angles which are specifically in degrees, you should ALWAYS be using radians.
Hey dream dog, radians!! Always radians unless you see the degree symbol (and you'll never see it when doing things with Calculus)  ;D
Brilliant :)
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humble mango

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Re: 3U Maths Question Thread
« Reply #426 on: August 02, 2016, 04:58:39 pm »
0
This is another attempt at Q2.





Thank you so much!! Our teacher has given us practice sheets to do, but didnt really print out the answers or provide a walkthrough on how to complete them ( which i think weakens the point of doing them in the first place :P) Again, thank you.

RuiAce

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Re: 3U Maths Question Thread
« Reply #427 on: August 02, 2016, 06:28:07 pm »
+2
How do you do part iii, iv, and v   ???







Edit: Let's continue with this question.





Blech what a long post. By the way where do you get these questions - I feel as though most of them are noticeably harder than the current HSC.


« Last Edit: August 02, 2016, 09:19:25 pm by RuiAce »

massive

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Re: 3U Maths Question Thread
« Reply #428 on: August 02, 2016, 08:14:27 pm »
0
Hey how do you do part iii, that's the only part i don't get. (btw i'm sorry if im annoying you with all these projectile questions, i just have a few that I dont get  :-\ )

RuiAce

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Re: 3U Maths Question Thread
« Reply #429 on: August 02, 2016, 08:45:26 pm »
+2
Hey how do you do part iii, that's the only part i don't get. (btw i'm sorry if im annoying you with all these projectile questions, i just have a few that I dont get  :-\ )



I haven't forgetten your other question yet. I will get to it shortly.

conic curve

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Re: 3U Maths Question Thread
« Reply #430 on: August 02, 2016, 09:09:14 pm »
0
Am I doing something wrong?

RuiAce

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Re: 3U Maths Question Thread
« Reply #431 on: August 02, 2016, 09:21:12 pm »
+1
Am I doing something wrong?
From line 3 to line 4 do not take out the negative and complete the square in the form A - (Bt+C)2

Line 4 to line 5 made no sense. How did -3 and 6 become -1/2 and 1
« Last Edit: August 02, 2016, 09:23:10 pm by RuiAce »

conic curve

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Re: 3U Maths Question Thread
« Reply #432 on: August 02, 2016, 09:23:03 pm »
0
From line 3 to line 4 do not take out the negative and complete the square in the form A - (t+C)2

Line 4 to line 5 made no sense. How did -3 and 6 become -1/2 and 1

I factorised the whole thing by 6

RuiAce

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Re: 3U Maths Question Thread
« Reply #433 on: August 02, 2016, 09:23:57 pm »
+1
I factorised the whole thing by 6
If you factorised the whole thing by 6 that should be 18 there not 1/2.

Anyway, regardless of if you factorise the 6 out, put the negative back in there and complete the square.
« Last Edit: August 02, 2016, 09:45:51 pm by RuiAce »

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #434 on: August 02, 2016, 11:48:05 pm »
+1




I think I'd swing at Part (v) a little differently, I interpret the question differently. When it says precisely two distances from O, doesn't that mean it has two solutions? The wording is really weird, but I don't think it relates to the distance d given earlier in the question, nothing suggests that. So my interpretation would be that we just need to prove that, provided that the condition on U holds, then there are two values of d which satisfy the other conditions given.

This would make sense, provided the target is moving slow enough, it can hit it on the way up (one distance), or on the way down (another distance). At least I think. I just don't think it relates to the distance d. What do you reckon Rui?  ::)