OCR MEI FP1 Thread - AM 20th May 2016

I don't know why but I feel like I wrote the wrong numbers down on the last question. Like I know I got something like 8*10^-3, but I just have a feeling I had a brain meltdown and wrote down the wrong number...

I also know that I got the area of the triangle wrong and the A stuff, as well as the whole of the stupid method is series as well. In total I probably lost around 15 marks not including method marks. So I hope you guys are right and the grade boundaries are low

Reply 81

Osmium

1

Original post by Adam_AFC

Yes to both questions. They made use the cosine rule and 0.5ABsinC for only 2 marks.

You could treat it as two right angle triangles.

Reply 82

hoakenfull

1

Original post by Adam_AFC

Yes to both questions. They made use the cosine rule and 0.5ABsinC for only 2 marks.

You could split it into two right-angled triangles and use 0.5bh

Reply 83

Crozzer24

7

Original post by hoakenfull

For the Inverse of B did anyone else multiply the matrix A by (1/25)?

And 168 units squared for the first question? Area of the image of the triangle

Oh god what was the first triangle question? Was it to work out the area because I've just written down the co-ord after transformation not the area :frown:

Reply 84

gregsonog

1

Original post by Adam_AFC

Yes to both questions. They made use the cosine rule and 0.5ABsinC for only 2 marks.

You only had to do (base x height)/2 of the triangle. You could either split it up into two triangles (one above/below x-axis) or turn the paper so the hypotenuse was the base and use that and the height to the point /2

Reply 85

fp1wassocalm

here are my answers (that I can remember)

2)Determinant was 0 so matrix was singular and plots to invariant points

7)horizontal asymptote y=root2 verticals at 1 and -1
8)roots 1,5,4-i,4+i
10) converges to 3 as n~infinity
for the differences, 1st and last terms are the only ones that don't cancel which gives the formula

Reply 86

chemari1

2

Original post by fp1wassocalm

I agree, but annoying because an a will be around 63/64

that's just your opinion innit

Reply 87

-Gifted-

6

Original post by chemari1

that's just your opinion innit

He's just a troll, A will be around 55.

Reply 88

Jamesinatr

1

Did anyone else get something like this for the Argand?

Reply 89

-Gifted-

6

Original post by Jamesinatr

Did anyone else get something like this for the Argand?

YES. Thats what I got. I think it is right.

Reply 90

Jamesinatr

1

Original post by -Gifted-

YES. Thats what I got. I think it is right.

Awesome, thanks. Loci is my worst topic so I wanted to check.

Reply 91

-Gifted-

6

Original post by Jamesinatr

Awesome, thanks. Loci is my worst topic so I wanted to check.

I think you gotta mention that its pi/4 from the y axis .

Reply 92

chemari1

2

what were questions 7 and 9?

Reply 93

Kichelle

5

Did anyone get 420 for question 4.20

Reply 94

Jamesinatr

1

Original post by -Gifted-

I think you gotta mention that its pi/4 from the y axis .

At least I remembered to label the angles in the exam :smile:

Reply 95

username2620623

Original post by fp1wassocalm

here are my answers (that I can remember)

2)Determinant was 0 so matrix was singular and plots to invariant points

7)horizontal asymptote y=root2 verticals at 1 and -1
8)roots 1,5,4-i,4+i
10) converges to 3 as n~infinity
for the differences, 1st and last terms are the only ones that don't cancel which gives the formula

Yeah I agree, for the 3x3 matrices question did you get the eigenvalues (1/8, 7) and that the solutions form a sheaf?

Reply 96

OscarH98

1

Original post by fp1wassocalm

here are my answers (that I can remember)

2)Determinant was 0 so matrix was singular and plots to invariant points

7)horizontal asymptote y=root2 verticals at 1 and -1
8)roots 1,5,4-i,4+i
10) converges to 3 as n~infinity
for the differences, 1st and last terms are the only ones that don't cancel which gives the formula

I'm pretty sure all of those are incorrect, the determinant was 12, roots were 2 and -1/2. Converges to 2/3 and 6 terms don't cancel.

Reply 97

xX-MikeHunt-Xx

For question 7 did anyone else get A=6 & B=51

Reply 98

hoakenfull

1

For the graph question:

Cut the x-axis at +/- root3
Cut the y-axis at 9/4
Vertical asymptotes at -4 and 1
Horizontal asymptote at y=3
As x approaches positive infinity, y approaches 3 (the horizontal asymptote) from below.
As x approaches negative infinity, y approaches 3 from above.

x=1.1 y is -ve
x=0.9 y is +ve
x=-3.9 y is -ve
x=-4.1 y is +ve