Quadrants and Angles
In this section we will discuss about quadrants and angles.
On XY-plane let lines XOX' and YOY' are at right angles to each other.So these lines divides the XY -plane in four equal parts. Each part is known as Quadrant
The lines XOX' and YOY' are known as X-axis and Y-axis respectively.These two lines taken together are known as coordinate axes.
Region of XOY ----> I QUADRANT
Region of YOX ----> II QUADRANT
Region of X'OY' ----> III QUADRANT
Region of YOX' ----> I QUADRANT
Angle in Standard position:
An angle is said to be in standard position if its vertex coincides with the origin and the initial side coincides with positive direction of X-axis.
Angle in a quadrant :
An angle is said to be in a particular quadrant, if the terminal side of the angle in standard position lies in that quadrant.
Examples of quadrants and angles
Quadrant angle :
An angle is said to be a quadrant angle, if the terminal side coincides with one of the axes.
Triangle of reference :
If from any point P on the terminal side of an angle in standard position a perpendicular PM is drawn on x-axis, then the right angled triangle OMP, thus formed,is called the triangle of reference of the $\angle$XOP.
Co-terminal angle :
Two angles with different measures but having the same initial sides and the same terminal sides are known as co-terminal angles.
11th grade math
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