Week4, exercise 1, why error

[katieeehan20]

Hello,
I did the following code to show reflection over y axis, and I don’t know why it’s error. Can anyone give clue please? Is my reflection matrix wrong?
I tried [-2,-3][2,1] too, and it also shows error…

[Isaak_Kamau]

Hello, @katieeehan20
Your Matrix may not be a valid reflection matrix about the y-axis.
Try:
[[-1, 0], [0, 1]]