Why?

[little tartan]

https://youtu.be/z4qiMIocwoM?si=zyQCnR0gpiSYIjQE
(Sorry if this is a really stupid question, I'm in year 9 and I wanted to learn further level maths for fun and since I want to do it when I'm older)
On the first question, why do we need to find OX, AX etc??.
It's probably a stupid question but I just don't get why we need to find them to find the value of k?

[spare stirrup]

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[little tartan]

I didn't finish it and used the video to help but I just don't get it

[smoky timber]

Timestamp?

[little tartan]

Around 3 minute mark

[bold shell]

this is arguabnly the hardest topic in gcse

[little tartan]

Yeah I heard stuff about that, but I really like challenging myself and I kinda like maths

[bold shell]

thats good

this is kinda the same as most of the other vector questions yhou get

but you basically say

ill explain in a bit hang on

you lets say you have a line

and a point k on that line

you basically say

k is some constant multiplied by the full line

i cant draw rn but in a bit i can explain better

[bold shell]

and yo do it for two lines that both hvae point k on them

then solve simultatnously kinda

[little tartan]

Think I finally figured it out

[slow grail]

First of all, don't you ever call another one of your questions "stupid" ever again! The very act of questioning is what helps you reach a higher level of understanding towards a subject as daunting as this one.

The reason we find OX, AX, etc is exactly because of what you put in your work (which I found to be fantastic, by the way)! Give this lecturer's video another watch again, if you have to, because he was also confusing me as well, I'm not going to lie.

In any case: OA + AX + XD = OD. We cannot directly jump to finding "OD", because the only thing we are given is the ratio k:1 (And we don't even know what CD is!). But check out the other pieces of information we are given in the diagram. OA = a, and OC = c...etc...

Sometimes, information is just given to you to waste your time, but that is not the case in this situation! I applaud you for being able to figure out the problem so quickly!

[little tartan]

Thank you so much

[pseudo hatch]

does the controller serve a purpose

[slow grail]

You’re welcome!

[little tartan]

Yeah

[tardy sorrel]

@little tartan hey am an As student and I really commend you for learning these maths

more students should take the initiative to learn more about a particular subject with curiosity even tho they are not required to at the moment

This is one of the harder concepts for vector other than the rare vector area ratio questions that come in IGCSE

[little tartan]

Yeah that's what I'm doing currently, it has no relation to what I'm learning in school. I'm just learning it for fun

[tardy sorrel]

in O levels hardest topics to grasp I think is calculus

this is one of the contenders also

[bold shell]

ehh, i think it's easy to understand and apply at this level, caus you only lern the power rule and that dy/dx is just a gradient function

idk

[craggy trout]

@little tartan

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[little tartan]

+close

[craggy trout]

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[pseudo hatch]

+close