$\text{-} (a,b)

(\text{-} a, \text{-} b)

= S t \overset{a}{˚} r d e t e t t m i n u s t e c k e n f r a m f \overset{o}{¨} r [[K o o r d i n a t f o r m f \overset{o}{¨} r v e k t o r * W o r d l i s t * ∣ k o o r d i n a t f o r m e n]] f \overset{o}{¨} r e n [[V e k t o r * W o r d l i s t * ∣ v e k t o r]] k a n m a n s k r i v a o m d e t t a g e n o m a t t s \overset{a}{¨} t t a i n m i n u s t e c k n e t f r a m f \overset{o}{¨} r b \overset{a}{˚} d e

x

- o c h

y$-koordinaten.

- (4, 6) = (- 4, - 6) .