Definitive list of proofs for HL Maths PII

Prowetod

The order I will do the questions will most likely be: 8,1,4,5,6,2,3.

Does anyone know if the line transformation proofs come up in Q3 often?

awhir

doorknob_opener wrote: »

I tried making it look ''mathsy'', you know with fractions ect..., but the usual mathods I use on a different forum didn't work . Since I can't make powers, ^2 means to the powers of 2. And to make it clear, all angles are in brackets.

1. cos^2(A) + sin^(2) = 1

2. Cosine formula a^2 = b^2 + c^2 - 2bc cos(A)

3. cos(A+B) = cos(A)cos(B) - sin(A)sin(B)

4. cos(2A) = cos^2(A) - sin^2(A)

5. sin(A+B) = sin(A)cos(B) + cos(A)sin(B)

6. sin(2A) = 2sin(A)cos(A)

This is where this might get hard to understand. By / I mean a fraction

7. tan(A+B) = [tan(A) + tan (B)]/[1 - tan^2(A)]

8. tan2A = [2tanA]/[1 - tan^2(A)]

9. cos2A = [1 - tan^2(A)]/[1 + tan^2(A)]

10. sin2A = [2tanA]/[1 + tan^2(A)]

11. cos^2(A) = 1/2[1 + cos(2A)]

12. sin^2(A) = 1/2[1 - cos(2A)]

If I typed anything wrong let me know. Good luck deciphering

do you have to learn all these or could u just prove them using common sence ?

gota study all of Q8,Q4,Q5 in 3hours its gona be tough !

Killaqueen!!!

Des23 wrote: »

Has the difference equation proof ever come up?
Could definitely see it happening, people usually take it as a straightforward 20 marks, if they are out to mix things up a bit...

2007

It's an annoying enough proof...what it is your actually proving? I know how to do it but I dunno what it is I am doing! It ends up equal to zero or something..

sock puppet

Not really sure how I'm going to go in this paper. I always go way over time on the circle question. I'll probably make it up on probability though.

And can someone help me with the proof of sin(a+b)? My book says to use the formula for cos(a-b) and substitute (pi/2 - a) in for a. Does cos(pi/2-a) = sin a?

platypus

sock puppet wrote: »

Not really sure how I'm going to go in this paper. I always go way over time on the circle question. I'll probably make it up on probability though.

And can someone help me with the proof of sin(a+b)? My book says to use the formula for cos(a-b) and substitute (pi/2 - a) in for a. Does cos(pi/2-a) = sin a?

Yes for this proof you need to remember cos(90-A)=sinA and sin(90-A)=cosA

sock puppet

sock puppet wrote: »

Not really sure how I'm going to go in this paper. I always go way over time on the circle question. I'll probably make it up on probability though.

And can someone help me with the proof of sin(a+b)? My book says to use the formula for cos(a-b) and substitute (pi/2 - a) in for a. Does cos(pi/2-a) = sin a?

Sin(90-A) is equal to cos(A), likewise, cos(90-A) = sin(A). It makes sense if you do a few examples on your calculator. For example:

Sin(90-30) = cos(30); sin(60) = cos(30). It's basically because, simply, cosine and sine are two sides of the one coin.

ya-ba-da-ba-doo

^ yeah cos(pi/2-A)=sinA and sin(pi/2-A)=cosA

xOxSinéadxOx

awhir wrote: »

do you have to learn all these or could u just prove them using common sence ?

gota study all of Q8,Q4,Q5 in 3hours its gona be tough !

no you don't have to learn them. they're just the trig identities
the proofs are
Circle:
Tangent Theorem

Line:
Angle between 2 lines
Perpindicular Distacen

Trig:
Cos^2A + Sin^2A = 1
compund angle formulae
cosine rule

Discrete Maths:
difference euqation theorem

trying to learn these all now :(

spent all day yesterday studying maths and I'm still screwed. I've done no irish either
aarrrgh