eager estuary
I'm trying to find a mnemonic that even though R(0,0),90∘(x,y)=(−y,x) and R(0,0),−90∘(x,y)=(y,−x) both inverse x & y that the difference is the '-' position. I came up with something but I'm not sure I'll remember it: the '-' in on the quadrant/2 position. Is there a better mnemonic?
Thank you kindly
sullen flint
I'm trying to find a mnemonic that even though ``R(0,0),90∘(x,y)=(−y,x)`` and `...
If you're doing rotations, do you know trig?
eager estuary
Not much, I'm doing Integrated Math.
sullen flint
Not much, I'm doing Integrated Math.
Okay, that kind of sucks, because that would make this pretty easy.
eager estuary
I'm just trying to find words association or a simple formula, the latter like the one in the OP.
sullen flint
Okay, well, if you're just interested in where the minus is, like, you just need to notice that each quadrant has a different arrangement of the signs on the x and y coordinates.
In Quadrant I, both are positive. In Quadrant II, y is positive. In Quadrant III, neither is positive. In Quadrant IV, x is positive.
eager estuary
Sorry about the delay. I'm looking for the 2 specific formulas in the OP, the one I made an image for.
And it needs to be easy to remember.
sullen flint
...is that not easy to remember?
Like, it's basically inherent to the definitions of the quadrants.
eager estuary
Not really but I think I got one: In positive angle direction, the 1st 1 is the 1st term and the 2nd is on 2nd term.
sullen flint
Not really but I think I got one: In positive angle direction, the 1st 1 is the ...
...what?
Look. The left side of the x axis is negative. The bottom of the y axis is negative.