Vectors... those damn vectors

Hi! Does anyone who does GCSE Maths or HAS done, know how to do the Vector questions? Those are the 5 mark, really tricky grade 8-9 questions towards the back of Paper 1 or 3 (I think 1 or 3) and our teacher won’t teach it to us. I can’t find it online and it wouldn’t help even if I could, I’d really appreciate the help.

thankyou!! Also if you can explain the Sin/Cosine triangle équation as well I’d love it? It’s for the equation in the photo. Thanks!

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Reply 1

username3818132

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Reply 2

YouAreAYute

vectors!!!!!!! arent!!!!!!!!!!!! maths!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Reply 3

the bear

you can upload your pic to postimage.org and then post the link here.

Reply 4

username3818132

Original post by YouAreAYute

vectors!!!!!!! arent!!!!!!!!!!!! maths!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

vectors is in maths. It is also in physics. Vectors is found in the GCSE content as well as in the as level content of pure mathematics and mechanics.

Reply 5

AlexJJCan

Original post by YouAreAYute

vectors!!!!!!! arent!!!!!!!!!!!! maths!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Vectors are maths!!!!! They appeared in the old GCSEs, clearly the new ones, A Level Maths C4 and all Mechanics modules!

Anyway, have you checked the TES website? Teaching resources may be found there. If not, maybe try emailing the head of faculty/maths or just get a tutor for a few sessions

Hope this helps

Reply 6

YouAreAYute

Original post by neluxsan

vectors is in maths. It is also in physics. Vectors is found in the GCSE content as well as in the as level content of pure mathematics and mechanics.

doesnt convince me, i refuse to care about them

Reply 7

notvincey

Original post by neluxsan

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Argh bugger- it’s the (half)abSinC rule for non right angled triangles

Reply 8

notvincey

Original post by YouAreAYute

doesnt convince me, i refuse to care about them

But I mean... it’ll get you another 5 marks so 😂 have you never seen them at the end of Papers ? It’s a shape with different lines and ABCDE etc labels and it asks you the angle or distance or something eh

Reply 9

username3818132

Original post by YouAreAYute

doesnt convince me, i refuse to care about them

You need to know at least some basics to get good grade

In summary:

Vectors are direction dependent: so if you force a vector the opposite side, you multiply its magnitude by -
Component vector when added up make resultant vector
This is a cheat, but still: if you trace your way from one point to another and find the shortest possible logical route to another point, which are trying to work out the vector for, then add the vectors going through that route, taking in consideration of the direction, so if it is opposite direction, you are effectively subtracting it

You need to care about them to get good grades. Its important!!

Reply 10

YouAreAYute

Original post by notvincey

yeah loool i had it in my mocks and got full marks

bu still

Reply 11

username3818132

Original post by notvincey

Argh bugger- it’s the (half)abSinC rule for non right angled triangles

that formula is used to work out the area of a non right angled triangle. I don't understand what you are asking?

Reply 12

notvincey

Original post by neluxsan

Thanks for this by the way!

Original post by neluxsan

that formula is used to work out the area of a non right angled triangle. I don't understand what you are asking?

I can’t comprehend some mathematical concepts without actually understanding HOW they work. As in I won’t remember that formula unless I can understand why that helps to find the angle. It’s why I do better with circle theorems and areas and compound interest etc than vectors and trig

Reply 15

username3818132

(half)abSinC

Lets do some computational thinking and decompose the formula. (Decomposition is the process of breaking down large problems into smaller problems that can be solved to solve the larger problem)

SinC - this is the angle between the two sides which are taking to find out the area. (you will understand this later when you read on). By doing inverse sin, you will be able to find out the angle (again explained more clearly further down)

"a" and "b" are two sides, which you are taking the length. These two side must meet each other (so "a" must meet "b") and you must know the angle between them in order to take these lengths.

(half) - area of triangle - its standard

For GCSE, you don't need to know how the formula came about

To find angle in a question, I assume they gave you the area(or you might have to work it out somehow) and they have given you the length (or you might have to work it out). Don't worry, only one type of information might be missing, so you only need to find out one thing most of the times.
If you rearrange the formula of (half)abSinC to make C (the angle) the subject, you would get C = (Area*2)/(ab), which you can use to work out angle

Reply 16

notvincey

Original post by neluxsan

Thank you so much, this genuinely helps me so much, and I’ll remember it now because I actually understand it :biggrin:

Reply 17

username3818132

That's good. No problem in helping :smile:

Reply 18

JustHannah_

I’m doing GCSE maths as well and know of some really great maths revision sites and apps that would definitely explain vectors in full detail! Corbettmaths and BBCbitesize are the best websites I’ve found. Corbettmaths in particular is really useful since they have countless videos, worksheets and exam papers and it’s all free, and it also comes with answer sheets to check your answers and improve

Reply 19

notvincey

Original post by JustHannah_

Thanks! Our teacher uses corbettmaths for everything so I didn’t actually consider it but with the amount of content we havent done it’s definitely worth having a look for the grades 7-9 stuff thinking about it