Question

please help see attached info

Answer 1

Is it the matrix multiplication you're struggling with?

Answer 2

yes

Answer 3

I'll write (1,1) to mean first row and first column. Then to multiply out matrices we do (1,1)*(1,1) + (1,2)*(2,1). That gives the value for the top left corner. So in that problem we get 2a - 4 =2 from that.

Alternatively you can think of matrix multiplication as a collection of scalar (or dot) products. For the above one, we take the dot product of the first row of the first matrix, with the first column of the second matrix.

Answer 4

ok thanks think i got it

Answer 5

can you help with vectors

Answer 6

Yes :)

Answer 7

ok I'll attached

Answer 8

Which bits?

Answer 9

the first one

Answer 10

i dont understand how to do no.3

Answer 11

Since JM=(1/3)JK, M must be a third of the way along the line JK.

Answer 12

yes but< but do i work out the answer to get JK

Answer 13

MN and KL

Answer 14

Well we can just multiply up in equation to give JK = 3JM = 3u. Or if you like you can think of it as since its a third of the way along we need three of them to go the way along.

Answer 15

ok I was thinking 3u, but was not sure

Answer 16

Yes that's right.

Answer 17

so MN will MJ+JN=1/3u+1/3V

Answer 18

and how do i get KL is it JK +KL=u+v

Answer 19

Mn is MJ+JN but MJ=-u not 1/3u since we are just going backwards along the same line. Also JN is v.

Answer 20

Think of KL as going from K to J and then J to L. So KL = KJ + JL.

Answer 21

are we not writing the expression in terms of u and v

Answer 22

Yes, so MN = MJ + JN = -3u + v and KL = KJ + JL = -3u + 3v

Answer 23

and I dont understand MN, but JM is 1/3 of JK and JN 1/3 od JL

Answer 24

MN = MJ + JN. We know that JM = u so MJ = -u. So I've no idea why I wrote -3u. Sorry about that!

Answer 25

ok thanks

Answer 26

for no.4 is the ans. 3a+3b, 3/2a+1/2b, a+(-3/2+1/2b)=-1/2a+1/2b, 2a+2b, -3/2a+3/2b

Answer 27

AB = OB - OA = b - 3a.

Answer 28

and DX:DC 4:1, DX=2a+2b=4
DC:1/2a+1/2b and the ans is (-1/2a+1/2b, =1/2a+1/2b)

Answer 29

I'm struggling to follow your answers.....for the first part I get AB = b-3a, AC = (1/2)(b-5a), DC = (1/2)(b-a) and DX = 2b -a

Answer 30

what is the answer for the questios (ii) and(iii)
and for C,D,