Products as sums or differences (1 Viewer)

Carrotsticks

Retired
Joined
Jun 29, 2009
Messages
9,494
Gender
Undisclosed
HSC
N/A
Lol, I fudged my working in a practice topic test I was doing once for 2U and I got the mark for it :D
But I reading this thread I was freaking out because I've never heard of the product as sums or differences let alone done it in class. My question now is, could they ever ask a question on this in the HSC and if so, is it best I learn it? My textbook is maths in focus :mad: so I don't think it has it in there.
Highly unlikely they will ask for it in the HSC.

If they do, they will at least first ask you to prove the identity (which is simple enough).
 

Kimyia

Active Member
Joined
Oct 21, 2011
Messages
1,013
Gender
Female
HSC
2012
Uni Grad
2016
Highly unlikely they will ask for it in the HSC.

If they do, they will at least first ask you to prove the identity (which is simple enough).
Ok, thanks :) Am I screwed with just using maths in focus??....I think my library has Cambridge which I'm going to borrow once we get back.
 

Carrotsticks

Retired
Joined
Jun 29, 2009
Messages
9,494
Gender
Undisclosed
HSC
N/A
Ok, thanks :) Am I screwed with just using maths in focus??....I think my library has Cambridge which I'm going to borrow once we get back.
Maths in Focus only covers the basic questions for every topic. Enough for probably a low Band 6/high band 5

If you want difficult questions, get the Cambridge book.
 

Kimyia

Active Member
Joined
Oct 21, 2011
Messages
1,013
Gender
Female
HSC
2012
Uni Grad
2016
Maths in Focus only covers the basic questions for every topic. Enough for probably a low Band 6/high band 5

If you want difficult questions, get the Cambridge book.
Seriously? Because scraping an E4 is my goal atm :)
 

osak23

Member
Joined
Jan 15, 2012
Messages
97
Gender
Male
HSC
N/A
Can someone explain the mathmatics extension bands??
like e4 , e3 is band 5 or 6 etc..?
lol
 

Kimyia

Active Member
Joined
Oct 21, 2011
Messages
1,013
Gender
Female
HSC
2012
Uni Grad
2016
I think E4 is >45, E3 >35, E2 >25
 

812

New Member
Joined
Feb 25, 2011
Messages
28
Location
The gates of Mt Olympus
Gender
Female
HSC
2012
Can someone please help me with this question?

Prove the identity

(2cos0.5X - 1 - cosX)/(2cos0.5X + 1 + cosX) = (1 - cos0.5X)/(1 + cos0.5X)



(farrrrrrr....it's 12:40 on a Sunday night during school holidays.....and I'm doing maths.)
 
Last edited:

SpiralFlex

Well-Known Member
Joined
Dec 18, 2010
Messages
6,960
Gender
Female
HSC
N/A
Can someone please help me with this question?

Prove the identity

(2cos0.5X - 1 - cosX)/(2cos0.5X + 1 + cosX) = (1 - cos0.5X)/(1 + cos0.5X)




(farrrrrrr....it's 12:40 on a Sunday night during school holidays.....and I'm doing maths.)






 
Last edited:

812

New Member
Joined
Feb 25, 2011
Messages
28
Location
The gates of Mt Olympus
Gender
Female
HSC
2012
Wow thanks....you guys are good. How did you guys think of using the double angle formula on cosX? How do I think like that?

Anyway, I'm stuck on another question.

Prove the identity

(1 - tanXtan2X) / (1 + tanXtan2X) = 4cos^2(X) - 3
 
Last edited:

Carrotsticks

Retired
Joined
Jun 29, 2009
Messages
9,494
Gender
Undisclosed
HSC
N/A
We knew to use it because the RHS had half angle formula only, implying that we had to 'break down' the 'double angle' cosX to its half angle form with cos0.5x.

Use the terms of the question as a clue as to what to do

This will help you greatly with proving Trig Identities.

 

812

New Member
Joined
Feb 25, 2011
Messages
28
Location
The gates of Mt Olympus
Gender
Female
HSC
2012
We knew to use it because the RHS had half angle formula only, implying that we had to 'break down' the 'double angle' cosX to its half angle form with cos0.5x.

Use the terms of the question as a clue as to what to do

This will help you greatly with proving Trig Identities.

Thank you.

I got to the 4th step previously and got stuck....
 

Drongoski

Well-Known Member
Joined
Feb 22, 2009
Messages
4,247
Gender
Male
HSC
N/A
Carrots

I just love the compact and very crisp mathematical type-script. How do you do that? I only know a bit of TeX and can't get it that nice.
 

Carrotsticks

Retired
Joined
Jun 29, 2009
Messages
9,494
Gender
Undisclosed
HSC
N/A
Carrots

I just love the compact and very crisp mathematical type-script. How do you do that? I only know a bit of TeX and can't get it that nice.
I'm actually not using LaTeX.

I'm using a program called 'Math Type', which is extremely easy to use (and requires much less skill than TeX). They have all the templates for fractions, matrices etc ready for you, and you just need to fill in the details.

Once you've typed it all out in the program, simply copy paste all of it into a Microsoft Word document.

It appears in the word document as a .gif file all nice and ready.

However, MathType also has a function where you can type in LaTeX and it will automatically appear in proper Math form.
 

812

New Member
Joined
Feb 25, 2011
Messages
28
Location
The gates of Mt Olympus
Gender
Female
HSC
2012
I'm actually not using LaTeX.

I'm using a program called 'Math Type', which is extremely easy to use (and requires much less skill than TeX). They have all the templates for fractions, matrices etc ready for you, and you just need to fill in the details.

Once you've typed it all out in the program, simply copy paste all of it into a Microsoft Word document.

It appears in the word document as a .gif file all nice and ready.

However, MathType also has a function where you can type in LaTeX and it will automatically appear in proper Math form.
Did you have to buy it?
 

Carrotsticks

Retired
Joined
Jun 29, 2009
Messages
9,494
Gender
Undisclosed
HSC
N/A
Nah, you can have an unlimited free demo.

However, the demo has fewer templates and quick-shortcuts, so it takes a bit more time typing it out.

Nevertheless, things can be written out much more quickly than LaTeX.
 

812

New Member
Joined
Feb 25, 2011
Messages
28
Location
The gates of Mt Olympus
Gender
Female
HSC
2012
Nah, you can have an unlimited free demo.

However, the demo has fewer templates and quick-shortcuts, so it takes a bit more time typing it out.

Nevertheless, things can be written out much more quickly than LaTeX.
Can you still recall the download link for it? :D
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top