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Vectors

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I understand the method of the answer but I don’t get where they got 0.5 from
Of tantheta =0.5

Any help would be appreciated!

I’m taking a guess it’s related to the fact it’s perpendicular?
Reply 1
Avatar for JGLM
JGLM
15
Look at the i component divided by the j component (opposite over adjacent) :wink:
Edit: sorry other way round lmao
(edited 2 years ago)
Reply 2
Avatar for Yazomi
Yazomi
OP
21
Original post by JGLM
Look at the i component divided by the j component (opposite over adjacent) :wink:
Edit: sorry other way round lmao


Ahhh I see it now thanks!!

One more question if you don’t mind
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0B51A652-7227-4120-AC5D-A3C6BEFBA619.jpg.jpeg
Following on this question- for part ii) how can you tell c lies on OA?

Once again the method made sense after reading it but I can’t visualise where they concluded that info
Original post by Yazomi
Ahhh I see it now thanks!!

One more question if you don’t mind
68C1DB92-8A42-4892-A3D3-8F155A6F4AAE.jpg.jpeg
0B51A652-7227-4120-AC5D-A3C6BEFBA619.jpg.jpeg
Following on this question- for part ii) how can you tell c lies on OA?

Once again the method made sense after reading it but I can’t visualise where they concluded that info

I think the c lies on OA bit is only for the minimum value
Reply 4
Avatar for JGLM
JGLM
15
Original post by Qxi.xli
I think the c lies on OA bit is only for the minimum value


And maximum value, the locus of c is a circle around A, so both the points with maximum and minimum values for |OC| lie on the line containing OA :wink:
Original post by JGLM
And maximum value, the locus of c is a circle around A, so both the points with maximum and minimum values for |OC| lie on the line containing OA :wink:

Ah but for the maximum value, it's not ON the line anymore, it's extended from OA?
Reply 6
Avatar for Yazomi
Yazomi
OP
21
Original post by Qxi.xli
Ah but for the maximum value, it's not ON the line anymore, it's extended from OA?


Original post by JGLM
And maximum value, the locus of c is a circle around A, so both the points with maximum and minimum values for |OC| lie on the line containing OA :wink:


Could it be because calculating the value for max |OC| on OA would be the same as calculating max value of |OC| anywhere else? Or something like that
Reply 7
Avatar for JGLM
JGLM
15
Original post by Qxi.xli
Ah but for the maximum value, it's not ON the line anymore, it's extended from OA?


It’s slightly ambiguous, sometimes they consider “OA” to be the entire vector line that goes in that direction.
Reply 8
Avatar for JGLM
JGLM
15
Original post by Yazomi
Could it be because calculating the value for max |OC| on OA would be the same as calculating max value of |OC| anywhere else? Or something like that


So if |AC| is equal to 2, then the distance between the two points is 2, so the possible values of C form a circle around A with radius 2. The maximum and minimum points are at the points where the extended line OA intersects that circle, and so the maximum and minimum values are (|OA| +2) and (|OA|-2) respectively.
Reply 9
Avatar for Yazomi
Yazomi
OP
21
Original post by JGLM
So if |AC| is equal to 2, then the distance between the two points is 2, so the possible values of C form a circle around A with radius 2. The maximum and minimum points are at the points where the extended line OA intersects that circle, and so the maximum and minimum values are (|OA| +2) and (|OA|-2) respectively.

Ahhh I see it now thank you!!
Reply 10
Avatar for JGLM
JGLM
15
Original post by Yazomi
Ahhh I see it now thank you!!


No worries :-)

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