Edexcel FP1 Thread - 20th May, 2016

I've given up on that area of a triangle question :angry:

Reply 902

Original post by Zacken

Pull out a factor of 1/2 (or -1/2) and you should see that the remianing bit inside the bracket is rotation of angle 30 (or 60)

ii A is just finding the Det M, because the det is the scale factor, so ii (a) is 4, isn't it? Aren't you talking about part ii (b)?

Reply 903

TheMoon

Original post by iMacJack

This

It was really difficult for an area of a triangle question...

Maybe @kingaaran will help us!

Isn't it just two right-angled triangles? Because the two points P and Q have the same x coordinate so you can have 2 right angled triangles by splitting it up at the X axis?

Reply 904

Chirstos Ioannou

2

Original post by Zacken

Pull out a factor of 1/2 (or -1/2) and you should see that the remianing bit inside the bracket is rotation of angle 30 (or 60)

I didn't get it at all.

Reply 905

Zacken

22

Original post by iMacJack

ii A is just finding the Det M, because the det is the scale factor, so ii (a) is 4, isn't it? Aren't you talking about part ii (b)?

Huh, I guess you could do it that way. I just noticed that if pulled an factor of -1/2 out I'm left with a simple rotation inside.

Reply 906

WhatIsSleep

7

For that PQS question, I found an area formula which helped me work it out..

(I have attached it as an image but the source is http://www.mathopenref.com/coordtrianglearea.html)

So A is (3, 0)
B is (12, 12)
and C is (27, -18)

Ax=3, Ay=0
Bx=12, By=12
Cx=27, Cy=-18

Subbing those into the formula, I got 225 units^2

Honestly though, I tried drawing diagrams and everything...couldn't find a better way of doing it tbh

areaoftriangle.png18.3KB

Reply 907

Original post by Zacken

Pull out a factor of 1/2 (or -1/2) and you should see that the remianing bit inside the bracket is rotation of angle 30 (or 60)

I don't understand why you'd pull out a factor of a half?

Reply 908

Original post by Zacken

Huh, I guess you could do it that way. I just noticed that if pulled an factor of -1/2 out I'm left with a simple rotation inside.

Yeah I know - I mean didn't he ask for help on part (a), which is the scale factor?

Reply 909

MrZombieHugz

1

Hey does anyone have any predictions for this year? Cheers

Reply 910

Zacken

22

Original post by iMacJack

Yeah I know - I mean didn't he ask for help on part (a), which is the scale factor?

Urgh, sorry. I meant pull out a factor of 2. Then you get 2(rotation matrix) so the 2 is your scale factor.

Reply 911

fpmaniac

2

Original post by Zacken

Pull out a factor of 1/2 (or -1/2) and you should see that the remianing bit inside the bracket is rotation of angle 30 (or 60)

How would u know to pull out half

Reply 912

WhatIsSleep

7

Original post by TheRandomGenius

I've given up on that area of a triangle question :angry:

I found a solution which might help, somewhere on page 46 of this thread :P (I hope you're talking about the PQS question lol)

(Yeah look a couple of posts above this one)

Reply 913

TrueDAN

Original post by economicss

Could anyone show how to do question 14 please http://crashmaths.com/wp-content/uploads/2015/12/Coordinate-Systems-Worksheet.pdf really hard coordinate systems question, thanks! :smile:

That is a beastly question haha!! Just done the first part now! How far have you got?

Reply 914

Marxist

10

Anyone tried 2014 June R? I think it's a good paper tbh.

Reply 915

TheRandomGenius

6b anyone? (i and ii). I've gone around in circles and ended up in an algebraic mess.

https://7cba9babeb0db0ff9468853e0b2d0a80708ec59c.googledrive.com/host/0B1ZiqBksUHNYZGxseFBIQkphV0k/June%202013%20(Withdrawn)%20QP%20-%20FP1%20Edexcel.pdf

Reply 916

TheMoon

Original post by WhatIsSleep

For that PQS question, I found an area formula which helped me work it out..

(I have attached it as an image but the source is http://www.mathopenref.com/coordtrianglearea.html)

So A is (3, 0)
B is (12, 12)
and C is (27, -18)

Ax=3, Ay=0
Bx=12, By=12
Cx=27, Cy=-18

Subbing those into the formula, I got 225 units^2

Honestly though, I tried drawing diagrams and everything...couldn't find a better way of doing it tbh

I don't understand, isn't it like two right angled triangles which you can use 1/2 base times height with?

I tried drawing it, obviously I've drawn it very inaccurately (terrible paint skills) since it doesn't look like a normal but is it something like this? Might be wrong. Sorry if I'm completely wrong with how it looks.

This gets 225 anyway.

Reply 917

Music With Rocks

9

Just to check when rearranging matrices does the term always go to the front so if
AB=C

A=B^-1C
and
B=A^-1C

Or is this wrong? it looks wrong

Reply 918