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AQA FP4 25th May 2016 Discussion Thread

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Original post by Number Nine
I'm a see what unofficial says on that but think I got it

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How did you do it?
Original post by C0balt
How did you do it?


Subbed in y = mx + c and showed it works for m = -1 and any value of c

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Original post by Number Nine
Subbed in y = mx + c and showed it works for m = -1 and any value of c

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**** I thought of doing 3+2m=-2m-1 but I didn't in the end...
I just subbed into y'=mx'+c and didn't know what to do afterwards
But I think I had 4-4m+c=0 or something like that but the if m=-1 then c cannot be any value can it
Original post by C0balt
**** I thought of doing 3+2m=-2m-1 but I didn't in the end...
I just subbed into y'=mx'+c and didn't know what to do afterwards
But I think I had 4-4m+c=0 or something like that but the if m=-1 then c cannot be any value can it


After doing y' = mx' + c I just showed cos I factored -2(m+1)(c+2) when m = -1 c can have any value as the whole expression is 0

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Original post by Number Nine
After doing y' = mx' + c I just showed cos I factored -2(m+1)(c+2) when m = -1 c can have any value as the whole expression is 0

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Ah that's clever
Original post by C0balt
Ah that's clever


Cheers fam



Are we the only two who have sat it lol
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What are people saying about predicted grade boundaries for that?
Original post by Barbecuetime123
What are people saying about predicted grade boundaries for that?


Note yet

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Original post by Number Nine
Cheers fam



Are we the only two who have sat it lol
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Appears that way :tongue:

Did y'=mx'+c then got (3+2m)x+(-2m-1)y+4-4m+c=0 or something which hopefully gets me a mark or two lmao

How did you find the paper overall? I
Original post by C0balt
Appears that way :tongue:

Did y'=mx'+c then got (3+2m)x+(-2m-1)y+4-4m+c=0 or something which hopefully gets me a mark or two lmao

How did you find the paper overall? I


Then you sub in y = mx + c

Alright pretty standard think I got most **** bar like posting a comment on why pi1 and pi3 don't meet.

You?

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Reply 130
My answers. Some of these may be wrong.
1) 3root22/2
2)detb =-1/32 (cant remember exactly)
3)-7(a-4)(a+1)(cant remember third factor)
4)z= 17/4 a
x =-11/6 a
Y= cant remember
5) p=-11
Lambda =2, -2,7
6) y=3/2 x -2
All lines of the form y=3/2 x +k are invariant lines (edit: I believe this is wrong)
7) k = 1/8
T2: rotation 150° about y-axis
8) k=+-1
When k =1, two parallel planes, intersecting third plane
When k=-1, planes form a triangular prism.
(edited 7 years ago)
Original post by Number Nine
Then you sub in y = mx + c

Alright pretty standard think I got most **** bar like posting a comment on why pi1 and pi3 don't meet.

You?

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I got y=-x+c was invariant under T hence infinite invariant lines.

Triangle was (3/2)root22 or (1/2)root22 I don't remember.

P was -11 i think.

I can't remember the rest, the last question with the variable planes and inconsistency, seemed a lot for 4 marks.
Original post by Qcomber
My answers. Some of these may be wrong.
1) 3root22/2
2)detb =-1/32 (cant remember exactly)
3)-7(a-4)(a+1)(cant remember third factor)
4)z= 17/4 a
x =-11/6 a
Y= cant remember
5) p=-11
Lambda =2, -2,7
6) y=3/2 x
All lines of the form y=3/2 x +k are invariant lines
7) k = 1/8
T2: rotation 150° about y-axis
8) k=+-1
When k =1, two parallel planes, intersecting third plane
When k=-1, planes form a triangular prism.


a-1 was 3rd factor, i think

I think you messed up something on 6.
Original post by Number Nine
Then you sub in y = mx + c

Alright pretty standard think I got most **** bar like posting a comment on why pi1 and pi3 don't meet.

You?

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Yeah it wasn't much different to past papers surprisingly
Though I disliked how the solutions for x y z where you had to use inverse matrix were messy fractions (I belive so anyway)
Oh yeah I hate commenting thing too, I said for k=1 pi1 and pi3 are parallel so no common line of intersection and for k=-1 I said they form a prism idk if that's right lol
Original post by Qcomber
My answers. Some of these may be wrong.
1) 3root22/2
2)detb =-1/32 (cant remember exactly)
3)-7(a-4)(a+1)(cant remember third factor)
4)z= 17/4 a
x =-11/6 a
Y= cant remember
5) p=-11
Lambda =2, -2,7
6) y=3/2 x -2
All lines of the form y=3/2 x +k are invariant lines
7) k = 1/8
T2: rotation 150° about y-axis
8) k=+-1
When k =1, two parallel planes, intersecting third plane
When k=-1, planes form a triangular prism.


I got -32 for 2
y=3/2x-2 for line of invariant points
210 degrees for rotation (same thing?)
Original post by Qcomber
My answers. Some of these may be wrong.
1) 3root22/2
2)detb =-1/32 (cant remember exactly)
3)-7(a-4)(a+1)(cant remember third factor)
4)z= 17/4 a
x =-11/6 a
Y= cant remember
5) p=-11
Lambda =2, -2,7
6) y=3/2 x -2
All lines of the form y=3/2 x +k are invariant lines
7) k = 1/8
T2: rotation 150° about y-axis
8) k=+-1
When k =1, two parallel planes, intersecting third plane
When k=-1, planes form a triangular prism.


Got pretty much the same, think Y was -41/12 a? I didn't cancel down though, so got -44/24, -82/24 and 102/24, do you think I'd lose a mark?
(edited 7 years ago)
Original post by C0balt
I got -32 for 2
y=3/2x-2 for line of invariant points
210 degrees for rotation (same thing?)

As long as you put which sense it is. The matrices on the formula sheet are for anticlockwise rotations.
what did you guys put for the question (i think 6 ?) where it asked you basically for the definition of invariant lines ?

+for question 4 i think i got integer coefficients and i can't remember any of 6 but i think the rest of mine were the same as what you're discussing ^ if i'm remembering right
What did everyone think of it ?
I personally didn't like 5,6 or 7 :/
Original post by Roxanne18
What did everyone think of it ?
I personally didn't like 5,6 or 7 :/


i didnt like 6 either. i thought it was a bit of a weird paper tho like the first few were nice and then the rest were kind of awful ?? like doable but not nice you know ??

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