** Higher Level Maths Paper 1 2012 Before/After **

cocopopsxx

2008 q8 (b) (ii) anyone? Please?

leaveiton

ChemHickey wrote: »

Finality is right

To get the argument. Get the tan of the angle as normal. Then, if it is in the third quadrant, treat it as like it was in the first quadrant, but add the angle to -pi. In the fourth quadrant, you take the angle you get and change the sign,

I hope this makes sense, I don;t do it this way but i think it may make a bit of sense.

Okay, I think that makes sense. So if it was the 4th quadrant, say, 1/-root3, you would say that the angle is equal to -pi/6, but the argument would be pi/6?

What way do you do it? Sorry, I just really don't understand all this because I wasn't in school when we did it!

DepoProvera

Protip: Use your calculator then you'll know what angle you should be getting

3rd Quad: -(pi-a)
4th Quad: -a
where a is the reference angle you get when you inverse tan.

mcpaddington

cocopopsxx wrote: »

2008 q8 (b) (ii) anyone? Please?

x + x/(x^2-1) = x^3/(x^2-1)
You can work it out from there. I just assumed that this is where you didn't understand.

leaveiton

DepoProvera wrote: »

Protip: Use your calculator then you'll know what angle you should be getting

3rd Quad: -(pi-a)
4th Quad: -a
where a is the reference angle you get when you inverse tan.

Thanks! I do tend to use my calculator, I'm just never sure what I should be doing when it comes to Quadrant 3 and 4!

One last thing though, sorry When working out the reference angle, do you take both values as positive? So in the example I described above, would I have been incorrect in saying pi/6, should it have been -pi/6?

deathbythelc

Quick question... Is it ok to use degrees for all the stuff you said above? And then if it specifies radians can you just convert your answer from degrees to radians?

DepoProvera

Yeah, degrees are sound for everything but integration.

deathbythelc

Thanks

DepoProvera

Yeah you do, because they are distances on the graph so they can't be negative.

But what I meant with the calculator is there is a POL button which will give you your r value and the correct angle when you punch in your x and y coordinates.

leaveiton

DepoProvera wrote: »

Yeah you do, because they are distances on the graph so they can't be negative.

But what I meant with the calculator is there is a POL button which will give you your r value and the correct angle when you punch in your x and y coordinates.

A what, sorry? Oh god I feel so stupid in this thread! I think I can do it by just finding the angle though, thanks so much for the explanation of that! Knowing me though I'll probably still manage to feck it up if it comes up tomorrow!

Dicksboro_man

Differentiation question here for you guys:

What does it mean if a graph has only one local turning point?

sarahmocks

DepoProvera wrote: »

Don't know if this cleared anything up for you...

You are a life saver!

DepoProvera

It gives you the polar form of coordinates. For Casio press [SHIFT] [+] [x coordinate] [SHIFT] [ ) ] [y coordinate] [=]

Mista

leaveiton wrote: »

Okay, I think that makes sense. So if it was the 4th quadrant, say, 1/-root3, you would say that the angle is equal to -pi/6, but the argument would be pi/6?

What way do you do it? Sorry, I just really don't understand all this because I wasn't in school when we did it!

I dont really get what other people are saying, i dont really get.like radians.. :P but when its in the 3rd, you add the reference angle to 180degrees, and in the 4th, you take the reference angle from 360 degree.

Mista

Dicksboro_man wrote: »

Differentiation question here for you guys:

What does it mean if a graph has only one local turning point?

Emm.. it only has 2 roots.. i think :S

Whats the function your differentiating?

leaveiton

DepoProvera wrote: »

Protip: Use your calculator then you'll know what angle you should be getting

3rd Quad: -(pi-a)
4th Quad: -a
where a is the reference angle you get when you inverse tan.

Mista wrote: »

I dont really get what other people are saying, i dont really get.like radians.. :P but when its in the 3rd, you add the reference angle to 180degrees, and in the 4th, you take the reference angle from 360 degree.

But surely these two things contradict each other? I'm really, really sorry to keep asking these questions, I feel like such a fool!

DepoProvera

Noooo! What he is saying is for trig! This is argand diagrams and complex numbers...

Mista

leaveiton wrote: »

But surely these two things contradict each other? I'm really, really sorry to keep asking these questions, I feel like such a fool!

Haha, no worries :P

The reference angle is less than 90degrees, so the angle in the 3rd must be less than 270degrees.. and the angle in the 4th is between 270 and 360

I mightened be explaining this very well..

DepoProvera

Mista wrote: »

Haha, no worries :P

The reference angle is less than 90degrees, so the angle in the 3rd must be less than 270degrees.. and the angle in the 4th is between 270 and 360

I mightened be explaining this very well..

This is wrong!

Mista

DepoProvera wrote: »

This is wrong!

Crap, sorry... is he not on about converting to polar form, no?

DepoProvera

Mista wrote: »

Emm.. it only has 2 roots.. i think :S

Whats the function your differentiating?

Aghhh our differentiation graphs will never have 2 roots. It's either 3 real distinct, 3 real 2 equal or 1 root.

deathbythelc

Reading this hurts my head.

ei.sderob

I'm gonna go ahead and clear this up.
1)Work out angle using tan (opp over adj)
2)1st quadrant leave it as it is.
2nd quadrant, take found angle from pi.
3rd qadrant, add found angle to pi.
4th quadrant, take angle from 2 pi.

leaveiton

Bet you anything this doesn't even come up :P

Champion Gold

Just read through this thread and I am emotionally breaking down here. I have spent all night spending geography and have an hour and a half tomorrow between tests to try and pass this test. I've never been so worried about a test in my life :O You all sound like you know everything. I can't believe I went from easy A in JC to this :P

deathbythelc

ei.sderob wrote: »

I'm gonna go ahead and clear this up.
1)Work out angle using tan (opp over adj)
2)1st quadrant leave it as it is.
2nd quadrant, take found angle from pi.
3rd qadrant, add found angle to pi.
4th quadrant, take angle from 2 pi.

THIS IS CORRECT.
USE THIS ONE.

KHJ

Should I leave out sequences and series or integration? Which one is harder?

ei.sderob

Yes...use that one:P

ei.sderob

I've completely left out sequences and series. Seemed more logical to have 7 questions down well rather than 8 sorta dodgy.

leaveiton

ei.sderob wrote: »

I'm gonna go ahead and clear this up.
1)Work out angle using tan (opp over adj)
2)1st quadrant leave it as it is.
2nd quadrant, take found angle from pi.
3rd qadrant, add found angle to pi.
4th quadrant, take angle from 2 pi.

Thank you so much, looking at some worked examples now and I finally understand