A Line
A ray starts at a point and extends forever in ONE direction. A line starts at a point and extends forever in TWO directions.
up and down it is the y axis on a graph
line
The imaginary line that extends straight out from the center of a reflective surface is the optical axis.
It extends in both directions (up and down) such that it is parallel to the y-axis.
x = 1 is a graph of a straight line that touches the x-axis at 1 and extends infinitely up and down.
A Line
Two, as it is a line.
A line or a plane.
A ray (line extends in both directions and line segment has two endpoints)
line
It is a vertical line.
A line (a line extends forever in both directions).
The imaginary line that extends straight out from the center of a reflective surface is the optical axis.
A ray starts at a point and extends forever in ONE direction. A line starts at a point and extends forever in TWO directions.
A horizontal line runs from side to side, while a vertical line extends up and down. The horizontal stabilizer is mounted on the tail of a plane and provides stability in level flight. In portrait mode, an image or display is narrower in horizontal measurement.