VCE Methods Question Thread!

[Corey King]

How much do you need in each exam for a 25 ss?

This depends on factors such as your student and school ranking, and how well the state does on the exam. Kelthing has a study score calculator. If you scroll up this page a bit, you should see a post by him with links to it's page

[Vainuba]

I was wondering why 0 is excluded from the set of values for why dy/dx is decreasing in Q2b.
 

[The Cat In The Hat]

I was wondering why 0 is excluded from the set of values for why dy/dx is decreasing in Q2b.

Have you checked the domain of the original function?

[SS1314]

I was wondering why 0 is excluded from the set of values for why dy/dx is decreasing in Q2b.

Remember functions are not differentiable at endpoints.

[Coolgalbornin03Lo]

What do I do if my CAS starts doing clock face in the exam? You know when you press enter to solve something but it’s having trouble?? It’s been 10 minutes and it’s still doing this

[keltingmeith]

What do I do if my CAS starts doing clock face in the exam? You know when you press enter to solve something but it’s having trouble?? It’s been 10 minutes and it’s still doing this

Restart it. Just a couple of quick questions, though:

a) What calculator are you using?
b) Exactly what calculation did you try to do? Preferably give it to us in calculator syntax, as you entered it on the screen

[Coolgalbornin03Lo]

Restart it. Just a couple of quick questions, though:

a) What calculator are you using?
b) Exactly what calculation did you try to do? Preferably give it to us in calculator syntax, as you entered it on the screen

The tnspire and resting didn’t work- that same equation made it stuff up again but all others are fine.

It was a circular function making derivative of the circular functions = tan(2)

[keltingmeith]

The tnspire and resting didn’t work- that same equation made it stuff up again but all others are fine.

It was a circular function making derivative of the circular functions = tan(2)

That's not enough information -  I want to know /exactly/ what you entered into the calculator to make it freeze up. I'm trying to figure out if there's a problem with your calculator, or you just entered something particularly hard for it. Don't even mind if you send it as a picture. And yeah, resetting won't let you do that equation again, because it's that equation that made it stuff up - resetting will just mean you get your calculator back for future questions.

[Coolgalbornin03Lo]

That's not enough information -  I want to know /exactly/ what you entered into the calculator to make it freeze up. I'm trying to figure out if there's a problem with your calculator, or you just entered something particularly hard for it. Don't even mind if you send it as a picture. And yeah, resetting won't let you do that equation again, because it's that equation that made it stuff up - resetting will just mean you get your calculator back for future questions.

Solve( -pi x sin(pix/30) + Pi/6) all divided by 2 = tan(2),x)

Sorry couldn’t upload a photo AN always says “it exceeds 3000kb or whatever   

[keltingmeith]

Yeah - so I imagine the calculator didn't like that because what it usually does is turn those circular functions into bigger equations - it's kind of the equivalent of you trying to evaluate:



Just a lot of stuff! It likely would've been easier if the numbers inside the circular functions were the same - since they weren't, that's where the problem was. But also, is that VCAA? Because I don't think you would expect to see this in VCAA, they don't like things that tend to crash calculators. Good news is, though, I don''t think this is a your calculator issue, just a general TI-nspire issue

[Coolgalbornin03Lo]

Yeah - so I imagine the calculator didn't like that because what it usually does is turn those circular functions into bigger equations - it's kind of the equivalent of you trying to evaluate:



Just a lot of stuff! It likely would've been easier if the numbers inside the circular functions were the same - since they weren't, that's where the problem was. But also, is that VCAA? Because I don't think you would expect to see this in VCAA, they don't like things that tend to crash calculators. Good news is, though, I don''t think this is a your calculator issue, just a general TI-nspire issue

Yes, it was the VCAA 2018 exam. That’s good to hear!!!
———————-—————————

In question 1e of the 2018 exam 2, why should there not be a negative sign in front of the intergral despite that part of the graph being below the x axis? And why should the intergral not be split in two? The examiners report said it should t and this is what I did.

Also on the CAS once you graph a relation, how do you go back to graphing non-relation graphs? On the same page? For example I’ve graphed the relation x= 2 but I’d like to graph f(x)= 2x^2 + 1 just to see where they meet.

In a circular function, if you have the angle and are trying to find gradient using m=tan(theta) should theta be in degrees or radians?

[MoonChild1234]

theta can be in either as far as im aware, but your CAS has to be in the corresponding DEG or RAD mode

if you are using the ti, you can click menu-graph entry/edit-Function (menu-3-1) and go back to graphing functions

Edit: for your 2018 exam question, there is no negative as it is the area between two functions, and you don't need a negative for those, despite it being under the x-axis. It doesn't have to be split in two, but it can be. I would imagine the examiners say not to as you can make more careless errors doing it and it is unnecessary.

hope this helped!

[Coolgalbornin03Lo]

theta can be in either as far as im aware, but your CAS has to be in the corresponding DEG or RAD mode

if you are using the ti, you can click menu-graph entry/edit-Function (menu-3-1) and go back to graphing functions

Edit: for your 2018 exam question, there is no negative as it is the area between two functions, and you don't need a negative for those, despite it being under the x-axis. It doesn't have to be split in two, but it can be. I would imagine the examiners say not to as you can make more careless errors doing it and it is unnecessary.

hope this helped!

Oh so it’s only negative when it’s the area between x-axis and function (even 2 functions?)

So if my calc is in radians it’s alright to put it in while in radians?

Thanks much moon child!

[dylan.kumar21]

Can someone help with this question? i do not understand which value for x to omit for part c
excuse the messy math 

[MoonChild1234]

Oh so it’s only negative when it’s the area between x-axis and function (even 2 functions?)

So if my calc is in radians it’s alright to put it in while in radians?

Thanks much moon child!

no worries! Yes it is fine to put it in radians but personally I would recommend degrees

You only put a neg in front of the integral when the area is with the function below the x-axis and the x-axis itself. Like you said, when it is between 2 functions, its just top-bottom function and you dont put a negative out the front, despite its location on the plane. LMK if this doesn't make sense