Definition:Cartesian Coordinate System/Quadrants

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Definition

For ease of reference, the cartesian coordinate plane is often divided into four quadrants by the axes:


First Quadrant

Quadrant-I.png

Quadrant $\text{I}: \quad$ The area above the $x$-axis and to the right of the $y$-axis is called the first quadrant.

That is, the first quadrant is where both the $x$ coordinate and the $y$ coordinate of a point are positive.


Second Quadrant

Quadrant-II.png

Quadrant $\text{II}: \quad$ The area above the $x$-axis and to the left of the $y$-axis is called the second quadrant.

That is, the second quadrant is where the $x$ coordinate of a point is negative and the $y$ coordinate of a point is positive.


Third Quadrant

Quadrant-III.png

Quadrant $\text{III}: \quad$ The area below the $x$-axis and to the left of the $y$-axis is called the third quadrant.

That is, the third quadrant is where both the $x$ coordinate and the $y$ coordinate of a point are negative.


Fourth Quadrant

Quadrant-IV.png

Quadrant $\text{IV}: \quad$ The area below the $x$-axis and to the right of the $y$-axis is called the fourth quadrant.

That is, the fourth quadrant is where the $x$ coordinate of a point is positive and the $y$ coordinate of a point is negative.


Note that the axes themselves are generally not considered to belong to any quadrant.


Sources