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#1 2006-11-20 03:56:34

Kiran
Member
Registered: 2006-11-15
Posts: 177

messed up do help me out

The vertices of triangle JKl are J(0,0) , K(3,-1) , L(-8,-7)
find the coordinates of the vertices after a reflection over the given axis : yaxis

i got wrong answer ..half answer

i wrote :
J = (0,0)
K = (-3,1)
L = (8,7)

HELP
please


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#2 2006-11-20 04:06:53

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

Re: messed up do help me out

The (8,7) is wrong.
It is (8, -7).
Can you visualize this?
(right,up) <--> (left,up)
You want to swap left and right.


igloo myrtilles fourmis

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#3 2006-11-20 04:29:26

Devantè
Real Member
Registered: 2006-07-14
Posts: 6,400

Re: messed up do help me out

The best thing to do is to actually draw a graph containing that triangle. It'll be a lot easier, unless you were asked not to do so, and/or it was a mental test.

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#4 2006-11-20 04:36:57

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: messed up do help me out

Adding to what John was saying, the (3,-1) coordinate becomes (-3,-1) when reflected as well.

To reflect any coordinate in the y-axis, you just need to put a minus in front of the first number (or take a minus away).


Why did the vector cross the road?
It wanted to be normal.

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