We will learn how to remember the trigonometric Formula in different quadrants.
1. Quadrant 1-(0° to 90°) - All functions are positive
2. Quadrant 2-(90° to 180°) - Sine & Cosec functions are positive
3. Quadrant 3-(180° to 270°) - Tan & cot functions are positive.
4. Quadrant 4-(270° to 360°) - Cos & Sec functions are positive
Now, Even Degree + angle = Same function
And
Odd Degree + angle = Opposite function
For Eg. Sine(180+x)= -Sinx as 180+x lies in 3rd quadrant where all are negative except tan & cot
Eg . Sine(270+x) = Cosx as 270 +x lies in 4th quadrant and 270 is an odd Degree ,so the opposite angle is cosine.
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