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March 28, 2024, 11:44:44 pm

Author Topic: VCE Methods Question Thread!  (Read 4802328 times)  Share 

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Sine

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Re: VCE Methods Question Thread!
« Reply #17520 on: January 01, 2019, 02:51:56 pm »
+1
I will try that next time!
All good.
Pi/2
So, a graph from pi/2  to 5pi/2 has a domain of length 2pi which is 1 period.

It doesn't really matter where it starts just make sure to show one full cycle (nothing more or less).

Evolio

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Re: VCE Methods Question Thread!
« Reply #17521 on: January 02, 2019, 10:10:05 am »
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Just to confirm, one period means one cycle right?

Lear

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Re: VCE Methods Question Thread!
« Reply #17522 on: January 02, 2019, 11:02:22 am »
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Yes
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studyingg

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Re: VCE Methods Question Thread!
« Reply #17523 on: January 02, 2019, 11:15:40 am »
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Just to confirm, one period means one cycle right?
Not for tan graphs, if by cycle, you mean a cycle around the unit circle

Evolio

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Re: VCE Methods Question Thread!
« Reply #17524 on: January 02, 2019, 12:13:14 pm »
0
Okay, thank you for your help Sine!
I really appreciate it!

Yes
Ok, thanks.

Not for tan graphs, if by cycle, you mean a cycle around the unit circle
Ok, thanks.

Evolio

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Re: VCE Methods Question Thread!
« Reply #17525 on: January 02, 2019, 12:47:15 pm »
0
Hi again.
So I have another question which is from the same attachment.
I am trying to do question c with intervals of pi/3. I drew the graph with intervals of pi/3 with the amplitude of 2. So, the range is -3 to 3.
When you sub in pi/3 into the equation how do you solve it to get the y value. ?
How do you do it on cas? It keeps saying missing) .

xdmemeguy

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Re: VCE Methods Question Thread!
« Reply #17526 on: January 02, 2019, 01:29:57 pm »
+3
Hi again.
So I have another question which is from the same attachment.
I am trying to do question c with intervals of pi/3. I drew the graph with intervals of pi/3 with the amplitude of 2. So, the range is -3 to 3.
When you sub in pi/3 into the equation how do you solve it to get the y value. ?
How do you do it on cas? It keeps saying missing) .

Can you post exactly what your CAS is saying?
I used the CAS and did it by hand and got the same answer.

I'm assuming it says "missing (" because you put it in like this into the CAS:



The calculator wont recognise this form you have to put in the 3 thats being multiplied inside the bracket like this:



@Evolio

I can also help you figure out the way to do it by hand if you would like.

Furthermore, the range is only [-2, 2] because only the 2 at the front alters the amplitiude which is two,

The 3 being multiplied inside the bracket changes the period.
« Last Edit: January 02, 2019, 01:35:49 pm by xdmemeguy »

Evolio

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Re: VCE Methods Question Thread!
« Reply #17527 on: January 02, 2019, 03:59:41 pm »
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Can you post exactly what your CAS is saying?
I used the CAS and did it by hand and got the same answer.

I'm assuming it says "missing (" because you put it in like this into the CAS:

(Image removed from quote.)

The calculator wont recognise this form you have to put in the 3 thats being multiplied inside the bracket like this:

(Image removed from quote.)

@Evolio

I can also help you figure out the way to do it by hand if you would like.

Furthermore, the range is only [-2, 2] because only the 2 at the front alters the amplitude which is two,

The 3 being multiplied inside the bracket changes the period.
Yeah I think I stuffed up the bracket stuff and the amplitude(not thinking properly).
I would like to be taught how to figure it out by hand please.  :D. Might make it easier.

S_R_K

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Re: VCE Methods Question Thread!
« Reply #17528 on: January 02, 2019, 04:24:54 pm »
0
There have been a number of posts on this in the past. This is a useful guide that was well-received, so perhaps this will help: https://atarnotes.com/forum/index.php?topic=7090.0

xdmemeguy

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Re: VCE Methods Question Thread!
« Reply #17529 on: January 02, 2019, 04:40:01 pm »
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Yeah I think I stuffed up the bracket stuff and the amplitude(not thinking properly).
I would like to be taught how to figure it out by hand please.  :D. Might make it easier.

sure

Its pretty simple and you need a knowledge of simple symmetry points and exact values to solve.

We start off by subbing in our value in our case pi/3



Then we gotta solve the inside of the sin function, start off by making the denominators the same.





Now the denominators are the same we add the two fractions



Now we multiply by the three and then simplify our fraction by three making it



Now to find the exact value of this, we use symmetry properties. Recognise our value is in the fourth quadrant which we will use to find the sign of our final answer. Sin in the fourth is negative. Now to find the magnitude we notice that our value is the same magnitude of \(\frac{\pi}{4}\) which is \(\frac{\sqrt{2}}{2}\). But we keep our negative sign as it is in the fourth quadrant making the answer to the whats inside the bracket \(-\frac{\sqrt{2}}{2}\) . Now the final step is the 2 which is being multiplied by the whole sin fucntion.  \(-\frac{\sqrt{2}}{2}\) times 2 is \(-\sqrt{2}\) making that the final answer

Im not 100% if I explained that amazingly, its hard when typing lmao ask me to clear up anything.




Evolio

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Re: VCE Methods Question Thread!
« Reply #17530 on: January 02, 2019, 05:23:54 pm »
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Wait where did you get the 2 for the final step?
Don't you multiply by 3?

xdmemeguy

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Re: VCE Methods Question Thread!
« Reply #17531 on: January 02, 2019, 05:41:26 pm »
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Wait where did you get the 2 for the final step?
Don't you multiply by 3?

No the three is from inside of the bracket. The picture of question 1c you sent earlier has a 2 infront of the sin function.

Evolio

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Re: VCE Methods Question Thread!
« Reply #17532 on: January 02, 2019, 05:43:18 pm »
0
Oh okay.
Thank you for your help.
I really appreciate it. :)

There have been a number of posts on this in the past. This is a useful guide that was well-received, so perhaps this will help: https://atarnotes.com/forum/index.php?topic=7090.0
Thank you.

Evolio

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Re: VCE Methods Question Thread!
« Reply #17533 on: January 03, 2019, 10:55:50 am »
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Hi. I am having really big problems with methods and it's making me hate it. I am currently self learning the content. Right now, I'm doing circular functions. It's taking me 30 mins to do one question because it's so hard I have to take a lot of time to draw the graphs.
Does anyone have any tips,advice or things they did that helped them with this self learning stuff?
Anything would be appreciated



Lear

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Re: VCE Methods Question Thread!
« Reply #17534 on: January 03, 2019, 11:06:57 am »
+2
I would highly recommend watching some videos to help you understand topics. Learning from a textbook is sometimes quite hard.

Two channels that come to my mind are Khan Academy and Worm’s maths academy.

Worm’s directed at VCE methods and can be found here

https://www.youtube.com/user/andrewworm

I absolutely loved his videos and they were super useful.

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