VCE Specialist 3/4 Question Thread!

[lzxnl]

Hi this is from VCAA 2007 EXAM 1

I wasn't quite sure but is this enough for 4 marks?

You wouldn't write tan theta = pi/2 because, well, tan theta isn't pi/2. Theta is pi/2 and the tangent of that is undefined.
But the rest is fine. The question is only asking to see if you can simplify a quotient and then rewrite what you get in polar form.

[lucas.vang]

thanks

[allstar]

a helicopter is rising with constant velocity 20m/s. When the helicopter is 60m above the ground a parcel is dropped. Find an equation in the form gt^2 + bt +c = 0 where g is the magnitude of the acceleration due to gravity and b and c are integers which when solved will give the exact time the parcel hits ground.

This is what I did but the ans says c = -120, i had +120?

please?

[Bestie]

can someone please help me:

shade the region {z:IzI <equal to 1} intersection {z: arg(z) <equal to arg(w)} in a argand diagram?

thank you

[BLACKCATT]

For 2.cos(x) = sqrt3.Cot(x)

Why is the general solution for Cos(x)=0, (2n+1)pi/2 and not (2n-1)pi/2? (what the cas says)

[Robert123]

For 2.cos(x) = sqrt3.Cot(x)

Why is the general solution for Cos(x)=0, (2n+1)pi/2 and not (2n-1)pi/2? (what the cas says)

The last two are essentially identical since they differ by one cycle, so both are correct since they are the same.

[LiquidPaperz]

if a question has parts a,b,c,d

and in c they require you to find x answer and round to 2 d.p, and in part d they require the use of the calculation in part c, are we meant to use the 2dp or all the ones the cas gives (i.e. 9-10) ?

thanks

[keltingmeith]

if a question has parts a,b,c,d

and in c they require you to find x answer and round to 2 d.p, and in part d they require the use of the calculation in part c, are we meant to use the 2dp or all the ones the cas gives (i.e. 9-10) ?

thanks

You should use the answer with more decimal places - it's much more precise.

[lzxnl]

The last two are essentially identical since they differ by one cycle, so both are correct since they are the same.

They actually differ by half a period of the cos function

[lucas.vang]

For questions with logs, is it okay if we leave it in modulus form loge|3| when the answer says loge(3) ?

[keltingmeith]

For questions with logs, is it okay if we leave it in modulus form loge|3| when the answer says loge(3) ?

It's not wrong... Pretty stupid thing to write, though. I think you're better off not.

[lucas.vang]

yeah I've notice I've been leaving it in that form lol, well thanks I'll make sure to fix it up

[lucas.vang]

Another question, when it says find an anti-derivative do we use c?
In Itute, they don't use it and in some VCAA papers they do and they dont, there not consistent

[psyxwar]

Another question, when it says find an derivative do we use c?
In Itute, they don't use it and in some VCAA papers they do and they dont, there not consistent

do you mean an antiderivative?

You don't need to write c, but I'd do it anyway.

[lucas.vang]

yeah anti-derivative sorry, okay thanks