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# Parametric equations - core Watch

1. Hello I need some help with the following question:

The origin in terms of co ordinate geometry is regarded at the (0,0). I found the values of X which = (3q,0) and Y = (0,4). If O is the origin which = (0,0), and OX=2OY, surely this would mean (0)(3q)=2(0)(4)? Why is this not correct I'm confused , the value of q=8/3, why ?
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2. (Original post by Cool-Light)
Hello I need some help with the following question:

The origin in terms of co ordinate geometry is regarded at the (0,0). I found the values of X which = (3q,0) and Y = (0,4). If O is the origin which = (0,0), and OX=2OY, surely this would mean (0)(3q)=2(0)(4)? Why is this not correct I'm confused , the value of q=8/3, why ?
why are you multiplying by zero?!
3. (Original post by Cool-Light)
Hello I need some help with the following question:

The origin in terms of co ordinate geometry is regarded at the (0,0). I found the values of X which = (3q,0) and Y = (0,4). If O is the origin which = (0,0), and OX=2OY, surely this would mean (0)(3q)=2(0)(4)? Why is this not correct I'm confused , the value of q=8/3, why ?
I don't see where the problem is!

Distance OX = 3q
Distance OY = 4

You're told that OX = 2OY so 3q = 8 and q = 8/3 as required.
4. (Original post by Cool-Light)
Hello I need some help with the following question:

The origin in terms of co ordinate geometry is regarded at the (0,0). I found the values of X which = (3q,0) and Y = (0,4). If O is the origin which = (0,0), and OX=2OY, surely this would mean (0)(3q)=2(0)(4)? Why is this not correct I'm confused , the value of q=8/3, why ?
OX is simply the x coordinate of X, and OY is the y coordinate of Y so OX=2OY is simply saying that 3q=8
5. Ahhh, I feel like ripping my hair out. I understand bits and pieces, but I don't understand why not simply write X=2Y, rather than writing OX=2OY. I thought I'd substitute the value of X and Y into the equation, and as the origin is (0,0) I'd sub that in also, hence why I thought is multiply it out but this is wrong, why..?
6. (Original post by Cool-Light)
Ahhh, I feel like ripping my hair out. I understand bits and pieces, but I don't understand why not simply write X=2Y, rather than writing OX=2OY. I thought I'd substitute the value of X and Y into the equation, and as the origin is (0,0) I'd sub that in also, hence why I thought is multiply it out but this is wrong, why..?
OX means the distance from O to X i.e. |OX|, which is essentially the actual coordinate of x since we measure from the origin.
7. (Original post by TeeEm)
OX means the distance from O to X i.e. |OX|, which is essentially the actual coordinate of x since we measure from the origin.
OHHH, mother. Thank youu
8. (Original post by Cool-Light)
OHHH, mother. Thank youu
no worries ...
9. Okay suppose O equals (3,4), would this then mean: 4(3q)=2(12), which would mean 12q=24, therefore q would = 2? Is this the correct way to approach this?
10. (Original post by TeeEm)
no worries ...
LOOL I'll try too... Last question:
suppose O equals (3,4), would this then mean: 4(3q)=2(12), which would mean 12q=24, therefore q would = 2? Is this the correct way to approach this?
11. (Original post by Cool-Light)
LOOL I'll try too... Last question:
suppose O equals (3,4), would this then mean: 4(3q)=2(12), which would mean 12q=24, therefore q would = 2? Is this the correct way to approach this?
No

then you have to use the distance formula to find an expression for distance(remeber the "square root formula for distance between points" from your C1
12. (Original post by TeeEm)
No

then you have to use the distance formula to find an expression for distance(remeber the "square root formula for distance between points" from your C1
I don't remember the equation, but I'm
13. (Original post by Cool-Light)
I don't remember the equation, but I'm
Ahh I remember this!
14. (Original post by Cool-Light)
Ahh I remember this!
all good
15. (Original post by TeeEm)
all good
I need to put pen to paperand work this out later, currently in a lesson! Just got told off . Wondering if you could help me later or whenever?
16. (Original post by Cool-Light)
I need to put pen to paperand work this out later, currently in a lesson! Just got told off . Wondering if you could help me later or whenever?
I will not unfortunately because I start teaching at 15.30 but I ma sure there many good people around.

all the best.

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Updated: January 21, 2015
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