Question

true or false? a closed half plane has a solid line for the boundary

Answer 1

True

1) Considering that a half-plane is:

2) Then we can state that if it is a closed half-plane, then the points on the line are included.

3). Therefore, if it is closed then we can represent that with a solid line

if it is open we do it with a dashed one.

Then, it is true.