VCE Methods Question Thread!

[knightrider]

In terms of trignometry

For the graphs what are the things you need to label

[bobisnotmyname]

In terms of trignometry

For the graphs what are the things you need to label

all the points of intrest, intercepts and highest lowest point

[keltingmeith]

For trig graphs, you should also indicate the median line.

[Outclass]

Can someone please solve this for me?

(-30/pi)cos[pi/30(x+45)]+3x=200

Thanks

[knightrider]

For these types of graphs how do you determine whether it is a cos or sin graph

[kinslayer]

For these types of graphs how do you determine whether it is a cos or sin graph

Technically any sine graph is also a cosine graph and vice versa, since . If you give me any sine graph I can just apply that transformation and give you an identical cosine graph.

This one is probably intended to be written with a cosine, because where t = 0, W is at a maximum, just like a cosine graph. You would then be expected to write down

[LiquidPaperz]

State the rule connecting y and x for each of the following graphs:

Spoiler

d) y=1/2x^2 +1 e) y=−1/2x^2+6 f) y= 1/2x^2

Thanks!

[keltingmeith]

First thing to notice is that the independent variable isn't x, it's either or .

Now, for the first graph, we have . We know that they're proportional to each other due to the straight line. However, we also need to consider the fact that this line DOESN'T go through the origin, which means we actually have . Now, substituting the y-intercept into the equation, we get . Now, we just need to find the gradient, which can be done in any way you like. I'm going to use the point (4,3), knowing that , not x.




Therefore, for d, . Use this same method to try and find the rules for the next two linear graphs.

[LiquidPaperz]

thanks, and for this question it asks to express y in terms of x but answer has A? how do you figure out the answer

BTW, what is the exact value of tan(-pi/3) ?

[keltingmeith]

Same way I did above. If something has in there, it is still in terms of x.

The exact value of tan(-pi/3) is

[Rod]

Hey Euler and others

Can you please show me how to do all of question 2c

http://www.vcaa.vic.edu.au/Documents/exams/mathematics/2008mmcas2-w.pdf

Spent a while thinking last night but then got too frustrated, opened it up today as wel and I still unfortunatly don't know where to start.

[keltingmeith]

Using all the bounds they've given us, we can draw them on and see that we have a trapezium. So, using the area of the trapezium, we have . Expanding at this point should not be necessary.

Next, we want to find out when this equals 7. So, we get:


(note: I used an online calculator because lazy, you'll be fine to just chuck this into the CAS).

(iii) I'll leave to you, because you now have the answers to give the thinking to answer this. (also because it relies on prior answers)

[Rod]

Using all the bounds they've given us, we can draw them on and see that we have a trapezium. So, using the area of the trapezium, we have . Expanding at this point should not be necessary.

Next, we want to find out when this equals 7. So, we get:


(note: I used an online calculator because lazy, you'll be fine to just chuck this into the CAS).

(iii) I'll leave to you, because you now have the answers to give the thinking to answer this. (also because it relies on prior answers)

Ahh you beast, thank you

Just one more sorry, from the same exam, q 3b. Like that other question, I just don't know where to start, don't really understand what the question is asking me.

[Rod]

Using all the bounds they've given us, we can draw them on and see that we have a trapezium. So, using the area of the trapezium, we have . Expanding at this point should not be necessary.

Next, we want to find out when this equals 7. So, we get:


(note: I used an online calculator because lazy, you'll be fine to just chuck this into the CAS).

(iii) I'll leave to you, because you now have the answers to give the thinking to answer this. (also because it relies on prior answers)

Just with this one though, I'm struggling to see where you get the trapezium. Don't we only find out the area of CA?

[IndefatigableLover]

Ahh you beast, thank you

Just one more sorry, from the same exam, q 3b. Like that other question, I just don't know where to start, don't really understand what the question is asking me.

With 3b, you would have found the time it takes to get the antidote whilst here you would use the formula:

Distance = Speed x Time (Transpose to make Time the subject)

And then you do it for the time it takes to run from the jungle and beach and you will see that the time it takes will not be enough for him to get his antidote