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March 28, 2024, 10:26:36 pm

Author Topic: 3U Maths Question Thread  (Read 1230220 times)  Share 

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jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #240 on: June 27, 2016, 06:35:46 pm »
+2
But I mean if I see a question unanswered for 3 hours and you guys are MIA... :P

Will undoubtedly happen on many more occasions so you are welcome to answer as many or as few as you like  ;D

jakesilove

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Re: 3U Maths Question Thread
« Reply #241 on: June 27, 2016, 06:35:46 pm »
+3
But I mean if I see a question unanswered for 3 hours and you guys are MIA... :P

Actually I would've written this one out just cause of the triangle haha

So you're saying I win? Pretty sure that means I win. Take heed kiddos; the HSC is not a competition, but Maths sure is.
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140498

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Re: 3U Maths Question Thread
« Reply #242 on: June 28, 2016, 08:20:48 pm »
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Moderator Action: Added LaTex formatting for easier reading.



Find all values for x for which f[g(x)] = x = g[f(x)].
« Last Edit: June 28, 2016, 10:06:54 pm by jamonwindeyer »

RuiAce

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Re: 3U Maths Question Thread
« Reply #243 on: June 28, 2016, 09:06:44 pm »
+1
If f(x) = 2 - (x)1/2, x ≥ 0 and g(x) = (x-2)2, for all x. Find all values for x for which f[g(x)] = x = g[f(x)]







Moderator Action: Question Fixed.
« Last Edit: June 28, 2016, 10:07:14 pm by jamonwindeyer »

140498

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Re: 3U Maths Question Thread
« Reply #244 on: June 28, 2016, 10:08:47 pm »
0
If f(x) = 2 - (x)^1/2, x ≥ 0 and g(x) = (x-2)^2, for all x. Find all values for x for which f[g(x)] = x = g[f(x)]

the (1/2) and 2 are both powers I forgot to put them in sorry

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #245 on: June 28, 2016, 10:13:25 pm »
+1
Moderator Action: Added LaTex formatting for easier reading.



Find all values for x for which f[g(x)] = x = g[f(x)].

Hey, welcome to the forums!!  ;D I think I interpret the question differently than Rui, I'd do the following (very brief, the full working would be similar to Rui's)




But this gives the same result as Rui anyway. Could you perhaps upload a photo of the original question?  ;D

PS - Let me know if you need any help finding your way around the forums  :)

140498

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Re: 3U Maths Question Thread
« Reply #246 on: June 28, 2016, 10:36:25 pm »
0
If f(x) = 2 - (x)^1/2, x ≥ 0 and g(x) = (x-2)^2, for all x. Find all values for x for which f[g(x)] = x = g[f(x)]

the (1/2) and 2 are both powers I forgot to put them in sorry

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #247 on: June 28, 2016, 10:47:36 pm »
+1
If f(x) = 2 - (x)^1/2, x ≥ 0 and g(x) = (x-2)^2, for all x. Find all values for x for which f[g(x)] = x = g[f(x)]

the (1/2) and 2 are both powers I forgot to put them in sorry

Ahhhhh okay cool, let's try again:





There we go, I hope that helps!  ;D

140498

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Re: 3U Maths Question Thread
« Reply #248 on: June 28, 2016, 10:52:24 pm »
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That's what I got but the questions asks for values (plural) which made me unsure

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #249 on: June 28, 2016, 11:35:10 pm »
+1
That's what I got but the questions asks for values (plural) which made me unsure

Even when asking for all values, one is still acceptable!! Let me take another look though...

Oh, I did forget to take into account the fact that the square root of the first line can be positive or negative!! This would create a second option:



So actually, taking into account that first option, any value of x greater than or equal to zero will work!! Wow, what a difference a little sign error can make (I can never go more than a few weeks without making one of these)  ;) sorry about that! Does this make sense?  :)


140498

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Re: 3U Maths Question Thread
« Reply #250 on: June 28, 2016, 11:48:54 pm »
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I understand how you got to where you are, I do not however know how to express the answer that is what is troubling me.

jamonwindeyer

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Re: 3U Maths Question Thread
« Reply #251 on: June 29, 2016, 12:17:36 am »
+1

I understand how you got to where you are, I do not however know how to express the answer that is what is troubling me.

Sure! So having reached that point, you would likely write something like this:



Does that help? ;D

WLalex

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Re: 3U Maths Question Thread
« Reply #252 on: June 29, 2016, 07:53:38 am »
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Hey was wondering if someone could please help me out with this strange binomial question for the 2009 HSC.
I even had a look at the answers and had absolutely no idea how to do it :P

I know its long...sorry and thanks in advance :)
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RuiAce

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Re: 3U Maths Question Thread
« Reply #253 on: June 29, 2016, 10:03:18 am »
+3
Hey was wondering if someone could please help me out with this strange binomial question for the 2009 HSC.
I even had a look at the answers and had absolutely no idea how to do it :P

I know its long...sorry and thanks in advance :)
Pulling strings here having me do a whole page...!







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RuiAce

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Re: 3U Maths Question Thread
« Reply #254 on: June 29, 2016, 10:23:39 am »
+1
Even when asking for all values, one is still acceptable!! Let me take another look though...

Oh, I did forget to take into account the fact that the square root of the first line can be positive or negative!! This would create a second option:



So actually, taking into account that first option, any value of x greater than or equal to zero will work!! Wow, what a difference a little sign error can make (I can never go more than a few weeks without making one of these)  ;) sorry about that! Does this make sense?  :)
I understand how you got to where you are, I do not however know how to express the answer that is what is troubling me.
Sure! So having reached that point, you would likely write something like this:



Does that help? ;D
I disagree