vector (1 Viewer)

[synthesisFR]

sometimes they ask for three solutions while other times they ask for one solution
obv this is based on if it follows the convention of naming shapes ie abcd and abdc and stuff like that but which is more correct to do?

 

[carrotsss]

I talked to my teacher about this recently, and unless there’s ambiguity about if it’s plural (I doubt there would be in the HSC) then you can just give 1 (eg if they say “a solution” then it’s 100% fine to just give 1)

 

[Drongoski]

Q19

If A, B, C are supposed to be 3 consecutive vertices, in cyclic order, (adjacent sides BA and BC), then there is only one D. In cyclic order, B-A-C (adjacent sides AB & AC) will generate another D and finally A-C-B (adjacent sides CA & CB) a 3rd D. A-B-C and C-B-A are treated as the same, etc etc.

Will provide solution after my lunch and afternoon news.

Q12 is a similar problem to Q19.

 

[Drongoski]

Q19

Don't know how to write a column matrix. So will use [a,b,c] instead.
For case A-B-C:



Therefore D is (-10,-1,3)

Is this a correct answer??

The other 2 D's can be similarly found.

 

[Drongoski]

Q12

Following same approach as for Q19:

(the position vector of point D)

 

[gazzaboy]

In this case, the order of the letters matters. In the first question, it just says it makes a parallelogram without specifying the order of the vertices. In the second question, they specify "ABCD", so it must mean that the vertices follow that order.