Ocr mei fp1 20/01/12

4ever_drifting

Anyone else take this today? How did you all find it? *waits for someone to compare answers with* :smile:

Reply 1

username512063

1

Original post by 4ever_drifting

Anyone else take this today? How did you all find it? *waits for someone to compare answers with* :smile:

Mememe! I think it was okay actually :biggrin:

Reply 2

chingchong

for the graph question did u guys get the negative part of the curve to start from above the y assymptote and then cross it and then converges to it from below?

Reply 3

username512063

1

Original post by chingchong

for the graph question did u guys get the negative part of the curve to start from above the y assymptote and then cross it and then converges to it from below?

Yes, this is correct. The other side converges from above.

Reply 4

bj_945

18

can anyone remember their answers to the alpha/2 +1 questions. i got 2w^3 - 11/2w^2 + 35/2w - 17/2. something like that anyway...? pretty sure i screwed up though.
and on Q8) the arguments as 0.644 and -0.644?

(edited 12 years ago)

Reply 5

skibur

12

bleugh, really disliked this paper, i got 72/72 yesterday on an fp1 paper and ive dropped so many on this one :frown:

Reply 6

chingchong

Original post by bj_945

can anyone remember their answers to the alpha/2 +1 questions. i got 2w^3 - 11/2w^2 + 35/2w - 17/2. something like that anyway...? pretty sure i screwed up though.
and on Q8) the arguments as 0.644 and -0.644.

well it would have been x= 2w-2 and i got a similiar equation nt sure if that equation u have thr is right

Reply 7

Malabarista

11

I got angles alpha and beta as being 0.848 and -0.848 or thereabouts. I used the half lines perviously drawn as tangents and did arg(alpha) = arcsin(3/4).

Reply 8

username512063

1

Original post by bj_945

can anyone remember their answers to the alpha/2 +1 questions. i got 2w^3 - 11/2w^2 + 35/2w - 17/2. something like that anyway...? pretty sure i screwed up though.
and on Q8) the arguments as 0.644 and -0.644?

The arg stuff was the only bits I didn't do, I found the rest pretty simple. The matrix bit at the end was nice.

Reply 9

karchun

2

This was one of the easiest papers of the lot...i just didn't really do the one asking for arg a and arg b - randomly guessed pi/4 and -pi/4 xD
the explanation near the end i thought was alright though i may have answered it s*** eg. why is RS = SR, i'm like because both matrices go anticlockwise therefore both 150 deg. no matter what the matrix multi. is! (probably wrong but :biggrin:

)

Also for the matrix S i used the cos(60), sin(60),-sin(60) and cos(60) (in up down order of 2x2)
and ended up getting 1/2, root 3 over 2, -root 3 over 2 and 1/2 :tongue:

hope it was right !

Reply 10

username512063

1

Original post by karchun

This was one of the easiest papers of the lot...i just didn't really do the one asking for arg a and arg b - randomly guessed pi/4 and -pi/4 xD
the explanation near the end i thought was alright though i may have answered it s*** eg. why is RS = SR, i'm like because both matrices go anticlockwise therefore both 150 deg. no matter what the matrix multi. is! (probably wrong but :biggrin:

)

Also for the matrix S i used the cos(60), sin(60),-sin(60) and cos(60) (in up down order of 2x2)
and ended up getting 1/2, root 3 over 2, -root 3 over 2 and 1/2 :tongue:

hope it was right !

I did everything you did here, except I didnt manage to guess for the arg question :biggrin:

Reply 11

4ever_drifting

OP

Original post by Malabarista

I got angles alpha and beta as being 0.848 and -0.848 or thereabouts. I used the half lines perviously drawn as tangents and did arg(alpha) = arcsin(3/4).

I did exactly this and have converted it to cartesian coordinates to check as well, so pretty sure it's right :smile:

Pretty nice paper IMO

Reply 12

bj_945

18

Yeah for the matricies that's perfect i think. What i got anway :P I put R as a reflection in the y-axis instead of rotation, such a bad move.
I just did tan-1( 3/4). And then did the pol() fucntion to double check.
Fairly nice paper overall though.

Reply 13

username512063

1

Original post by bj_945

Yeah for the matricies that's perfect i think. What i got anway :P I put R as a reflection in the y-axis instead of rotation, such a bad move.
I just did tan-1( 3/4). And then did the pol() fucntion to double check.
Fairly nice paper overall though.

Original post by 4ever_drifting

I did exactly this and have converted it to cartesian coordinates to check as well, so pretty sure it's right :smile:

Pretty nice paper IMO

Much better than I was expecting. I sat core 3 as well, which you might have guessed from TSR, was horrendous. FP1 made up though :biggrin:

Reply 14

karchun

2

Original post by LastHype

Much better than I was expecting. I sat core 3 as well, which you might have guessed from TSR, was horrendous. FP1 made up though :biggrin:

Seriously F* core 3 (aqa) so hard! Messed that up 10 times harder that FP1

Reply 15

username512063

1

Original post by karchun

Seriously F* core 3 (aqa) so hard! Messed that up 10 times harder that FP1

You're doing 2 different maths exam boards? The MEI one was equally rubbish.

Reply 16

matt.dickenson

Did anyone find the induction question equally, if not harder than the alpha/beta coordinates one? :L

Reply 17

MysteryTurtle

Original post by matt.dickenson

Did anyone find the induction question equally, if not harder than the alpha/beta coordinates one? :L

The induction question I found pretty straight forward got a bit fiddly when you had to take the +1 out and then a factor of 3 but you knew the result anyway so it was just getting to it (IMO ofc).

The alpha-beta question was confusing - it said arg(z) is a minimum which surely means its just 0? I drew a circle at 4 on the real axis with radius 3 but after that I was lost. I drew two tangents to the curve but I couldn't see where the argument came from as all you knew was the radius (hypotenuse) was 3. Anyone care to enlighten me?

Reply 18

4ever_drifting

OP

Original post by JumpingFrog

The induction question I found pretty straight forward got a bit fiddly when you had to take the +1 out and then a factor of 3 but you knew the result anyway so it was just getting to it (IMO ofc).

The alpha-beta question was confusing - it said arg(z) is a minimum which surely means its just 0? I drew a circle at 4 on the real axis with radius 3 but after that I was lost. I drew two tangents to the curve but I couldn't see where the argument came from as all you knew was the radius (hypotenuse) was 3. Anyone care to enlighten me?

I found the induction pretty straight forward as well. For the alpha beta question, arg(z) means the priciple argument - so from -pi to pi. So the minimum was the greatest negative argument. Hence A and B are 2 points such that lines through the origin and A/B are tangents with the circle. To find the angle you had to use trig: A tangent is always perpendicular to the line from the centre of the circle to the point where the tangent meets the circle, so you get a right angled triangle. Then since the centre of the circle is (4,0) the length of the side along the real axis is 4. (Call the triangle OAZ, where z is the centre of the circle. Then OAZ is a right angle, OZ is 4, ZA is 3, then it's just inverse sin)

Reply 19

css-

I know it was a pretty simple paper but I've dropped marks, just annoying more than anything.

Got 0.848 and -0.848 for arg alpha/beta, but only showed it for one and said the other one was because of symmetry because I ran out of time.

for the alpha/beta/gamma question i think i got 4w^3 + 22w^2 +19w + 35 (can't remember what the signs were really, but i zoned out completely during that question so it's probably wrong anyway) got p as -78 though i think, which i was pretty sure was right

got to the induction eventually, found it so fiddly though and so much was crossed out that i'll probably get 0 marks haha

got the same as mentioned above for the graph

can't remember anything else eeek :frown:

Ocr mei fp1 20/01/12

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