VCE Methods Question Thread!

[DrDusk]

Thanks, but where does y^2 come from (also, what's the rationale behind doing this method?)

The y^2 is just a random substitution. Your allowed to do this stuff. The rational behind it is that it takes away the square root, notice however you don't need to make this substitution. You can rather just do.

[KiNSKi01]

Yo can someone explain q10c Exam 1 2008

How do you change your answer into the form ax/bx+c (didn't understand how to do it after looking at examiners report)

[DrDusk]

Yo can someone explain q10c Exam 1 2008

How do you change your answer into the form ax/bx+c (didn't understand how to do it after looking at examiners report)

So we are required to find



Sub this into the equation for f(x)

[KiNSKi01]

Thankyouuu

Forgot about the negative in front of the log 

[EllingtonFeint]

Hey! So, I am shockingly bad at methods but I've done two years of it, so may as well do my best on the exam, right??
Anyways, I started doing some exam questions today and it literally took me nearly twenty minutes to get through the first two questions (well, q 1 part a and b, anyway) and now I'm stuck in q2

I have no clue what I'm doing with this question. At first I thought maybe I needed to differentiate it?? But I have no idea how to do that with that fraction so if anybody has a moment, could they please show me how to work it out?? So far, all I've managed to kinda work out is that I think I need to use the product rule?? But I don't really know 

Thank you!

[Nature]

Hey! So, I am shockingly bad at methods but I've done two years of it, so may as well do my best on the exam, right??
Anyways, I started doing some exam questions today and it literally took me nearly twenty minutes to get through the first two questions (well, q 1 part a and b, anyway) and now I'm stuck in q2

I have no clue what I'm doing with this question. At first I thought maybe I needed to differentiate it?? But I have no idea how to do that with that fraction so if anybody has a moment, could they please show me how to work it out?? So far, all I've managed to kinda work out is that I think I need to use the product rule?? But I don't really know 

Thank you!

Coming from a 1/2 student, I believe it's circular functions, needing to find the amplitude and see for what values it is a maximum. I don't think calculus is needed? unless you can find the stationary point and see where it is a maximum

[Matthew_Whelan]

Heres how I would approach it, either with or without CAS. Hopefully I didn't make an error. 
Pls forgive my spelling errors too. 

[EllingtonFeint]

Coming from a 1/2 student, I believe it's circular functions, needing to find the amplitude and see for what values it is a maximum. I don't think calculus is needed? unless you can find the stationary point and see where it is a maximum

Ohmigosh you're totally right! That makes sense

[EllingtonFeint]

Heres how I would approach it, either with or without CAS. Hopefully I didn't make an error. 
Pls forgive my spelling errors too. 

Ohhh! Okay, I'm starting to get it, but I don't really understand how you found pi t / 8 = those numbers??

(Thank you so much for your in depth explanation though!)

[DrDusk]

Ohhh! Okay, I'm starting to get it, but I don't really understand how you found pi t / 8 = those numbers??

(Thank you so much for your in depth explanation though!)

[undefined]

In your second line, shouldn’t
pi t/8 = +/-ArcCos(1/2) + 2k pi
since cos is positive in quadrant 1 and 4?
Also shouldn’t it be -pi/3 not 5pi/3 since it’s cos not sin

Edit: mb am tripping about the -pi/3 comment but I still think adding 2kpi onto the second line is better. Correct me if I'm wrong though

[harold17]

If I glue two books of different spine size together, and then put black binding tape over both books from Officeworks, will this be allowed for my bound reference?

[S_R_K]

In your second line, shouldn’t
pi t/8 = +/-ArcCos(1/2) + 2k pi
since cos is positive in quadrant 1 and 4?
Also shouldn’t it be -pi/3 not 5pi/3 since it’s cos not sin

Edit: mb am tripping about the -pi/3 comment but I still think adding 2kpi onto the second line is better. Correct me if I'm wrong though

You are correct. Inverse cos is one-to-one, so writing arccos(1/2) = x is effectively discarding all of the solutions outside 0 ≤ x ≤ pi.

I would not encourage Methods students who are unfamiliar with the domain/range of inverse circular functions to use them when solving equations with circular functions.

Much better is the usual approach of something like cos(x) = 1/2, so x = pi/3 + 2pik or x = 5pi/3 + 2pik, where k is an integer, and then make sure to include all and only solutions within the domain.

[studyingg]

Do we have to write our answer in the simplest form if the question does not explicitly specify to do so? Would an answer like 168/90 still be sufficient to get full marks, when it can be simplified further?

[Sine]

Do we have to write our answer in the simplest form if the question does not explicitly specify to do so? Would an answer like 168/90 still be sufficient to get full marks, when it can be simplified further?

fully simplified and exact values are required unless stated otherwise e.g. Give the answer in a certain type of form or to a certain number of decimal places.