Vectors: A is at point (2,3) and B is the point (-2,0).

[bumblebee123]

Hello All,

I wonder if someone can help me please.
I have a question I am stuck on, although I have done the first two parts I am unable to do the last two. I have no diagram only text. I will give the whole question because I think it is relevant to finding the answers to the parts I can't do. Questions are in italics.

A is at point (2,3) and B is the point (-2,0).
ai) Write AB(written with an arrow over the top pointing right) as a column vector.

I got this answer [-4,-3] written on top of one another but I don't know how to do that on here.

aii) Find the length of the vector AB(written with an arrow over the top pointing right) as a column vector.

I got the answer to this : 5


The part I can't do:

D is the point such that BD (written with an arrow over the top pointing right) is parallel to [0,1] (written on top of one another) and the length of AD (written with an arrow over the top pointing right) = the length of AB (written with an arrow over the top pointing right). O is the point (0,0)

b) Find OD (written with an arrow over the top pointing right) as a column vector

I don't understand the information they have given although I do understand that being parallel would mean that the line is a multiple of the other. I have drawn out the information on a grid but am still stuck. Please can someone explain what is being asked and how you get the solution? The answer is [-2,6] but I don't know how you get it.

The next part is just as hard for me:

C is the point such that ABCD is a rhombus. AC is a diagonal to the rhombus.

c) Find the coordinates of C.

Thank you in advance for your help.

 

[lev888]

D is the point such that BD (written with an arrow over the top pointing right) is parallel to [0,1] (written on top of one another) and the length of AD (written with an arrow over the top pointing right) = the length of AB (written with an arrow over the top pointing right). O is the point (0,0)

b) Find OD (written with an arrow over the top pointing right) as a column vector

I don't understand the information they have given although I do understand that being parallel would mean that the line is a multiple of the other. I have drawn out the information on a grid but am still stuck. Please can someone explain what is being asked and how you get the solution? The answer is [-2,6] but I don't know how you get it.

Can you post your drawing?
To find where D is you need to use the facts that
1. Vector BD is parallel to vector [0,1]. Can you draw vector [0,1]? Can you draw one possible vector BD? (we don't know its length yet)
2. Length of AD = length of AB (which is 5). So the point D is on the line through point B, parallel to [0,1] and at such coordinates that length of AD is 5.

 

[Steven G]

Hello All,

I wonder if someone can help me please.
I have a question I am stuck on, although I have done the first two parts I am unable to do the last two. I have no diagram only text. I will give the whole question because I think it is relevant to finding the answers to the parts I can't do. Questions are in italics.

A is at point (2,3) and B is the point (-2,0).
ai) Write AB(written with an arrow over the top pointing right) as a column vector.

I got this answer [-4,-3] written on top of one another but I don't know how to do that on here.

aii) Find the length of the vector AB(written with an arrow over the top pointing right) as a column vector.

I got the answer to this : 5


The part I can't do:

D is the point such that BD (written with an arrow over the top pointing right) is parallel to [0,1] (written on top of one another) and the length of AD (written with an arrow over the top pointing right) = the length of AB (written with an arrow over the top pointing right). O is the point (0,0)

b) Find OD (written with an arrow over the top pointing right) as a column vector

I don't understand the information they have given although I do understand that being parallel would mean that the line is a multiple of the other. I have drawn out the information on a grid but am still stuck. Please can someone explain what is being asked and how you get the solution? The answer is [-2,6] but I don't know how you get it.

Thank you in advance for your help.

A multiple of [0,1] looks like [0,k]. If you want the length to be 5, then this vector is [0,5]. If you put the tail of the vector BD at B = [-2, 0], then where would the head be at? This is simple vector addition.