OCR MEI FP1 (14th May 2015)

OP

Nice subject choices!
I'm studying Biology, Chemistry, Maths and Further Maths, hoping for A*AA (at least) overall for Biochemistry at Oxford, but am also looking at Sheffield, Warwick and York :smile:

Nice

I had an interview at Oxford, but unfortunately no offer. It was amazing.

Reply 21

YveT

Original post by SH0405

Nice

I had an interview at Oxford, but unfortunately no offer. It was amazing.

That really sucks :/ I hope you get what you need for Warwick, it's an amazing university!!

Reply 22

lucye7

Hi! In matrices what is the significance of a zero determinant?

Reply 23

YveT

Original post by lucye7

Hi! In matrices what is the significance of a zero determinant?

It means the matrix is singular (has no inverse) :smile:

Reply 24

tambeshakunt

2

Hi, Just a quick question:

When drawing complex numbers on an argand diagram, should you draw just a cross at the point or a line (with arrow) leading up to it from the origin??

The mark scheme usually shows just crosses but I believe the line w/arrow is the proper way?

Or does it really not matter?

Thanks.

Reply 25

SH0405

OP

15

Original post by tambeshakunt

Hi, Just a quick question:

When drawing complex numbers on an argand diagram, should you draw just a cross at the point or a line (with arrow) leading up to it from the origin??

The mark scheme usually shows just crosses but I believe the line w/arrow is the proper way?

Or does it really not matter?

Thanks.

I normally draw a line from the origin to the point (without an arrow). I'm sure they'll accept regardless of the presence of a line.

Reply 26

Bruhh

10

Original post by tambeshakunt

Hi, Just a quick question:

When drawing complex numbers on an argand diagram, should you draw just a cross at the point or a line (with arrow) leading up to it from the origin??

The mark scheme usually shows just crosses but I believe the line w/arrow is the proper way?

Or does it really not matter?

Thanks.

If they just ask for the point then a cross at those coordinates is correct. If they ask for the modulus of the complex number then you'd draw a line labelling it's length.

Reply 27

gmcoote

4

Original post by Bruhh

If they just ask for the point then a cross at those coordinates is correct. If they ask for the modulus of the complex number then you'd draw a line labelling it's length.

If they say modulus it will be written as mod | 2 - j | = 5 which would be a circle with radius 5 and centre 2 - j

Reply 28

Bruhh

10

Original post by gmcoote

If they say modulus it will be written as mod | 2 - j | = 5 which would be a circle with radius 5 and centre 2 - j

That would be |z-(2-j)| = 5 as the circle would represent the position where z could be, just |2-j| would be the distance from the origin to the point 2-j.

Reply 29

tambeshakunt

2

Ah ok thanks. Just that I have never seen a mark scheme where they have drawn a line with an arrow but I have learnt it that way :frown:

Reply 30

simon1207

1

Can someone answer this please:

In the mark scheme after proof by induction it gives the answer as (k +1)((k +1)+1)((k +1)+ 2)(3(k +1)+1)

what if i write (k+1)(k+2)(k+3)(3k+4)

will that still get me all the marks

Reply 31

Bruhh

10

Original post by simon1207

Can someone answer this please:

In the mark scheme after proof by induction it gives the answer as (k +1)((k +1)+1)((k +1)+ 2)(3(k +1)+1)

what if i write (k+1)(k+2)(k+3)(3k+4)

will that still get me all the marks

Lol whats with the weird font? But yeah it should do as it's still technically correct. But by splitting it into (k+1) just shows you understand more what you've just done. but you should still get full marks.

Reply 32

simon1207

1

Original post by Bruhh

Lol whats with the weird font? But yeah it should do as it's still technically correct. But by splitting it into (k+1) just shows you understand more what you've just done. but you should still get full marks.

Thanks

Reply 33

Darcy1

12

Could someone please explain how moduluses such as I z-4 I = 3 work? Is it just centre 4,0 with radius 3? Is there a rule i can follow to find the exact centre of the circle?

Reply 34

tambeshakunt

2

Original post by Darcy1

Could someone please explain how moduluses such as I z-4 I = 3 work? Is it just centre 4,0 with radius 3? Is there a rule i can follow to find the exact centre of the circle?

Yes you're right.

in general:

|z-(a+bj)|=r

where the centre is (a,b) and radius is r.

Reply 35

Dan205

8

I'm taking this tomorrow as well! The only bit I'm worried I'll muck up is if they ask us to find where where two loci intersect on an argand diagram (so far so good), but then ask us to find the arg of the intersection :/ it's only come up in two past papers so I've got my fingers crossed haha!

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