Coordinates

[acoustic rivet]

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[white crow]

what do u think the answer is

[pulsar yoke]

idk

[sick elk]

do you know how to reflect a point

[tight kite]

Note that two reflections in perpendicular axes are equivalent to inversion through the point of intersection of those axes. So, in this case, the origin.

[dusty plume]

multiply all the x coords by -1?

[tight kite]

Not just x. All coordinates.

[dusty plume]

mb i didnt see the y-coords part

[tight kite]

Oh, I see.
If you meant reflecting in the y-axis, then yes, we multiply all x-coordinates by -1.

In fact, in general, any composition of rotations and reflections is just a rotation or reflection, too. Quite useful.

Note that in the plane inversion and rotation by π are the same thing. They aren't the same in ℝ^3.

[pulsar yoke]

ok so uh

which one is that 😭

im a little slow

[tight kite]

Well, what happens to (x, y) when you invert it through the origin?

[pulsar yoke]

it reverses

to -x and -y

[pulsar yoke]

i did it myself thanks

+close