Maths help - Vectors

I got a 9 in my maths gcse but vectors have always stumped me.
Specifically ratio type vector questions.
I feel like I’m being a bit vague but usually my approach is to find two ways of getting the same vector, match up the constants and get the answer.
But apparently that doesn’t always work? I watched the GCSE Maths Tutor on YouTube for help - his method seems to be finding every vector then just going from there??
So I guess my question is, how do you do these types of questions?

Reply 1

mqb2766

21

Original post by marioo068

I got a 9 in my maths gcse but vectors have always stumped me.
Specifically ratio type vector questions.
I feel like I’m being a bit vague but usually my approach is to find two ways of getting the same vector, match up the constants and get the answer.
But apparently that doesn’t always work? I watched the GCSE Maths Tutor on YouTube for help - his method seems to be finding every vector then just going from there??
So I guess my question is, how do you do these types of questions?

Can you post a typical question?

Reply 2

marioo068

OP

4

Original post by mqb2766

Can you post a typical question?

https://imgur.com/a/uA8ztGB

(edited 6 months ago)

Reply 3

mqb2766

21

Original post by marioo068

I’m trying to but I’m unsure how to post an image :/

Just click on the camera icon on the reply toolbar, or paste a link if its already on the web.

Reply 4

marioo068

OP

4

Original post by mqb2766

Just click on the camera icon on the reply toolbar, or paste a link if its already on the web.

https://imgur.com/a/uA8ztGB

Hope that works

Reply 5

mqb2766

21

Original post by marioo068

https://imgur.com/a/uA8ztGB

Hope that works

Yes, youve not said how youd do it, but for me the aim is to work out ON as a fraction of OB=b by considering where it intersects with AP.

So OM = a + (b-a)/2, which gives OP as 3/5 of that.
That gives AP as A0+AP and by multiplying that by a scalar you can work out where it intersects with OB, which should give the result.

Edit - as an alternative, you could probably draw a horizontal across from M and argue about similar triangles (classic thales). Possibly simpler with a bit practice, though the vector approach seems more "handle turning"

Edit 2 - another geometry approach could be to draw the line MN and reason about the triangle areas.

(edited 6 months ago)

Maths help - Vectors

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