Vector

[upper cradle]

I genuinely need help i spent 1 hour trying to do this in class even my teacher don’t know how to do it it was on my mock paper 3

[livid owl]

r u sure u given the right amount i cause whats the other length @upper cradle

there is a length with a b what is it

but this is all u do ur inding two equations so u can get the ratios

i think maths geniie does good vidoes on tyhis

[jolly shadow]

Find QA as a vector in terms of k and find QA in another direction

And equate them

Simultaneous equations

To get k

To find AD you know that AD + DC = AC and you’re given DC and AC so firstly use that to get AD

[upper cradle]

Yeah im pretty sure its exact what the question said

[upper cradle]

So would QA be -3ka -3a

I tried to find QM and QN and then like say QN =xQM but idk i got some long answer

But the actual answer is 3/4

[jolly shadow]

I’ll solve it and send a solution

@upper cradle u sure the answer isn’t 4/3?

[upper cradle]

Oh yeah its 4/3 sorry

[jolly shadow]

Yh that’s what I got

Here’s my worked solution

[upper cradle]

For QM how did you get that? I keep getting it as -3ak -31/8a + 7/8b

Because BC is -a + b and CD is -3a and DN is 1/2a -1/2b
So i got -a + b -3a + 1/2a -1/2b

Oh nevermind thats QM

I did QN

I think i did the same thing as you i just didnt factorise the a out

How comes you have to do that

[jolly shadow]

Because the k is a scale factor so you factor out the a as the expression within that a is equal to the co-efficient of the a in that vector

It’s like if you did 3x+4x=7x

(3+4)x=7x

So 3+4=7

Or even if you did like 4x + kx = 9x

The reason why k is 5 cus you subtract 9 by 4 bit also cus 4+k=9

[upper cradle]

Ohh alrigjt thank you i get the whole thing now

This question was way harder than the actual 2025 one

Its from the shadow paper thing because it was in my mock