Login

Welcome, Guest. Please login or register.

March 29, 2024, 01:11:19 am

Author Topic: VCE Methods Question Thread!  (Read 4802420 times)  Share 

0 Members and 10 Guests are viewing this topic.

Azila2004

  • Trailblazer
  • *
  • Posts: 32
  • Respect: 0
Re: VCE Methods Question Thread!
« Reply #18480 on: March 28, 2020, 02:53:07 pm »
0
Hello,

Can someone please help me with the following question:
Find the set of values of k for which f(x)=3x^2-5x-k is greater than one for all real values of x.

Thanks!
Just someone who likes to learn a lot of questions.

Aspiring medical practitioner! ʕ•́ᴥ•̀ʔっ


2021: Biology, Psychology
2022: Mathematical Methods, Specialist Maths, English Language and Chemistry (We'll see!)

S_R_K

  • MOTM: Feb '21
  • Forum Obsessive
  • ***
  • Posts: 487
  • Respect: +58
Re: VCE Methods Question Thread!
« Reply #18481 on: March 28, 2020, 03:46:25 pm »
+1
Hello,

Can someone please help me with the following question:
Find the set of values of k for which f(x)=3x^2-5x-k is greater than one for all real values of x.

Thanks!

Every quadratic can be written in the form a(x – b)^2 + c. If a > 0, then, since (x – b)^2 ≥ 0, we have a(x – b)^2 + c ≥ c.

So write f(x) in the form a(x – b)^2 + c (your value for c will be an expression in terms of k) and then solve for the values of k that give c ≥ 1.

rukayabal

  • Adventurer
  • *
  • Posts: 13
  • Respect: 0
Re: VCE Methods Question Thread!
« Reply #18482 on: April 01, 2020, 04:14:08 pm »
+1
Hi all,
This is the first time I'm asking a method's question :) um... I was wondering whether ordinates are on the study design and if they do  come up on the exam. 
Thanks :)
« Last Edit: April 01, 2020, 04:29:03 pm by rukayabal »

TheEagle

  • Forum Obsessive
  • ***
  • Posts: 361
  • Respect: +12
Re: VCE Methods Question Thread!
« Reply #18483 on: April 01, 2020, 04:49:10 pm »
+2
Hi all,
This is the first time I'm asking a method's question :) um... I was wondering whether ordinates are on the study design and if they do  come up on the exam. 
Thanks :)

Welcome to the forums.

I'm assuming you're talking about addition of ordinates? If so, yeah it can come up, I believe it came up on last years exam (I remember someone on the forum saying so)

colline

  • MOTM: NOV 19
  • Forum Obsessive
  • ***
  • Posts: 341
  • ♡ 2 Timothy 1:7 ♡
  • Respect: +512
Re: VCE Methods Question Thread!
« Reply #18484 on: April 01, 2020, 06:11:14 pm »
+4
Hi all,
This is the first time I'm asking a method's question :) um... I was wondering whether ordinates are on the study design and if they do  come up on the exam. 
Thanks :)
Welcome to the forums.

I'm assuming you're talking about addition of ordinates? If so, yeah it can come up, I believe it came up on last years exam (I remember someone on the forum saying so)

Addition of ordinates was on the 2018 tech active VCAA exam :)

It’s not a topic that gets tested very often but since it’s on the study design, it could potentially come up!

VCE: Literature [50] Methods [50] Further [48] Chemistry [40] Biology [33]
2022: Bachelor of Science (Mathematical Economics) @ ANU

Sine

  • Werewolf
  • National Moderator
  • Great Wonder of ATAR Notes
  • *****
  • Posts: 5135
  • Respect: +2103
Re: VCE Methods Question Thread!
« Reply #18485 on: April 01, 2020, 06:56:11 pm »
+3
Hi all,
This is the first time I'm asking a method's question :) um... I was wondering whether ordinates are on the study design and if they do  come up on the exam. 
Thanks :)

Yes on the study design but as others have said it rarely comes up on the exam (which is not a good reason to not learn it though). As above it has come in the 2018 exam and before that, I believe the last time would've been in something like the late 90s.

S_R_K

  • MOTM: Feb '21
  • Forum Obsessive
  • ***
  • Posts: 487
  • Respect: +58
Re: VCE Methods Question Thread!
« Reply #18486 on: April 01, 2020, 08:35:59 pm »
+3
That question on the 2018 exam could also be done be sketching the graph of \(y=b(t), t \in [0,6]\) and then (for the part otherwise done by addition of ordinates) \(y=b(t) + b(t-6),t \in [6,12]\). More accurate, and also very quickly done because you've probably already defined b(t) on your CAS.

I think it's more likely for addition of ordinates to appear in multiple choice. Something like: "Here are separate graphs of y = f(x) and y = g(x) (no equations given), which of the following could be y = f(x) + g(x)?"
« Last Edit: April 01, 2020, 08:37:33 pm by S_R_K »

rukayabal

  • Adventurer
  • *
  • Posts: 13
  • Respect: 0
Re: VCE Methods Question Thread!
« Reply #18487 on: April 01, 2020, 09:00:48 pm »
0
Thanks guys. I Reallly appreciate your help :)

Crystal Phuong

  • Fresh Poster
  • *
  • Posts: 1
  • Respect: 0
Re: VCE Methods Question Thread!
« Reply #18488 on: April 07, 2020, 03:10:14 pm »
0
Hi guys, I'm a little confused about some content in Methods 1/2 so I hope you can help me!

We're currently going through Chapter 7, and for 7D (Determining Transformations) of graphs:

For a question such as "Find a sequence of transformations which takes the graph of. y= 3/(x-1)^2 +6 to the graph of y= 1/x^2,

and the answer was

"One transformation is a translation of 6 units in the negative direction of the y-axis and 1 unit in the negative direction of the x-axis followed by a dilation of factor 1 from the x-axis."

---> How do we know if the translation or dilation (or reflection) is done first? Or does the order not matter?

Thank you!

whys

  • VIC MVP - 2020
  • Forum Leader
  • ****
  • Posts: 722
  • Respect: +916
Re: VCE Methods Question Thread!
« Reply #18489 on: April 07, 2020, 03:23:59 pm »
0
Hi guys, I'm a little confused about some content in Methods 1/2 so I hope you can help me!

We're currently going through Chapter 7, and for 7D (Determining Transformations) of graphs:

For a question such as "Find a sequence of transformations which takes the graph of. y= 3/(x-1)^2 +6 to the graph of y= 1/x^2,

and the answer was

"One transformation is a translation of 6 units in the negative direction of the y-axis and 1 unit in the negative direction of the x-axis followed by a dilation of factor 1 from the x-axis."

---> How do we know if the translation or dilation (or reflection) is done first? Or does the order not matter?

Thank you!

Typically, the order transformations are done in is dilations, reflections then translations (considered the simplest order to give transformations in if the question asks you). You can still do translations first, however your answer will be different. Both answers are correct. The order doesn't matter as long as the question doesn't specifically ask you to write it in a specific order.
psych [50] bio [50]
2021-2025: BMedSci/MD @ Monash

TheEagle

  • Forum Obsessive
  • ***
  • Posts: 361
  • Respect: +12
Re: VCE Methods Question Thread!
« Reply #18490 on: April 07, 2020, 11:11:37 pm »
0
Hi guys, I'm a little confused about some content in Methods 1/2 so I hope you can help me!

We're currently going through Chapter 7, and for 7D (Determining Transformations) of graphs:

For a question such as "Find a sequence of transformations which takes the graph of. y= 3/(x-1)^2 +6 to the graph of y= 1/x^2,

and the answer was

"One transformation is a translation of 6 units in the negative direction of the y-axis and 1 unit in the negative direction of the x-axis followed by a dilation of factor 1 from the x-axis."

---> How do we know if the translation or dilation (or reflection) is done first? Or does the order not matter?

Thank you!


Hey!

I am doing 3/4 and have recently learnt a cool trick from the connect education book for methods;

If you are asked for the sequence of transformations where it goes from a 'simple' function to a more 'complex' function: then do DRT

However, if you are going from a more 'complex' function to a 'simple' function, then do TRD.


By simple, I mean something like y=x^2
By complex, I mean something like y=(x-5)^2 + 4
« Last Edit: April 07, 2020, 11:15:11 pm by TheEagle »

Snow Leopard

  • MOTM: SEP 19
  • Forum Leader
  • ****
  • Posts: 574
  • Respect: +196
Re: VCE Methods Question Thread!
« Reply #18491 on: April 10, 2020, 02:46:11 pm »
0
For perfect cubes, would it be correct to say that you shouldn't put in whether the a or b term is negative when subbing it into the equation to expand it?
For example:
for (4x-y)^3 you'd put in the b term, in this case the y as only "y" not "-y" into the equation: a^3 - 3a^2b + 3ab^2 - b^3

S_R_K

  • MOTM: Feb '21
  • Forum Obsessive
  • ***
  • Posts: 487
  • Respect: +58
Re: VCE Methods Question Thread!
« Reply #18492 on: April 10, 2020, 03:38:31 pm »
+2
For perfect cubes, would it be correct to say that you shouldn't put in whether the a or b term is negative when subbing it into the equation to expand it?
For example:
for (4x-y)^3 you'd put in the b term, in this case the y as only "y" not "-y" into the equation: a^3 - 3a^2b + 3ab^2 - b^3

Yes, because you're using the expansion of \( (a - b)^3\).

If you were using the expansion of \( (a + b)^3 \) then you'd use \(b = -y \).

moonchild

  • Trailblazer
  • *
  • Posts: 46
  • Respect: +29
Re: VCE Methods Question Thread!
« Reply #18493 on: April 11, 2020, 08:54:34 pm »
0
Hi there, im a little confused about a line of working - i've attached it to this :)) pls send help
for the step where 14=8x 2^-b - 2^-b (line 3), how does it simplify to 14= 7 x 2^-b? what happens to the -2^-b?
many thanks  ;D

ashmi

  • MOTM: June 20
  • Victorian Moderator
  • Forum Obsessive
  • *****
  • Posts: 429
  • Living an illusion
  • Respect: +660
Re: VCE Methods Question Thread!
« Reply #18494 on: April 11, 2020, 09:32:41 pm »
+3
Hi there, im a little confused about a line of working - i've attached it to this :)) pls send help
for the step where 14=8x 2^-b - 2^-b (line 3), how does it simplify to 14= 7 x 2^-b? what happens to the -2^-b?
many thanks  ;D

So on the third line, what you can do is actually factorise these numbers. ;D
(Original)  \[14 = 8\times 2^{-b}-2^{-b}\]
Factorising it (because 8 * 2^-b and -2^-b are factors) \[14 = (8-1)\times 2^{-b}\]
Then it equals \[14 = 7\times 2^{-b}\]
Hope that helps! ;D
(I need to so figure out how to write with Latex properly)
« Last Edit: April 11, 2020, 09:46:29 pm by ashmi »