Y Axis
The y-axis is the vertical number line in a Cartesian coordinate system that intersects the horizontal x-axis at a right angle. The point where these two axes intersect is called the origin. It is used to measure the vertical position, known as the ordinate, of a point in a two-dimensional plane.
Key Concepts
Every point located exactly on the y-axis has an x-coordinate, or abscissa, of zero, meaning its coordinates are always in the form (0, y).
The y-axis divides the Cartesian plane into left and right halves, with positive values extending upwards from the origin and negative values extending downwards.
The perpendicular distance of any point (x, y) from the y-axis is determined by the absolute value of its x-coordinate.
Formula & Equation
The equation of the y-axis is x = 0. The coordinates of any point on the y-axis are given as (0, y).
Here, x represents the horizontal distance from the origin which is always zero, and y represents the vertical distance from the origin.
Common Misconceptions
Myth: Students often think that the y-coordinate of a point on the y-axis is zero.
Fact: It is actually the x-coordinate that is zero on the y-axis. For example, a point 5 units up on the y-axis is written as (0, 5), not (5, 0). The y-coordinate is only zero on the x-axis.
Real World Applications
The vertical shaft of an elevator in a high-rise building, where the ground floor is the origin and floors above and below represent positive and negative y-values.
Measuring the altitude of an airplane or the depth of a submarine relative to sea level on a two-dimensional radar screen.
Frequently Asked Questions
What is the equation of the y-axis?
The equation of the y-axis is x = 0, because every point on this vertical line has a horizontal position of zero.
How do you find the distance of a point from the y-axis?
The perpendicular distance of a point from the y-axis is the absolute value of its x-coordinate.