Basic Trigonometric Ratios
Range of Values of Ratios
If 0 ≤ θ ≤ 360o, then the values for different trigonometric ratios will be as follows:
Sign of Trigonometric Ratios
We divide the angle at a point (i.e. 360°) into 4 parts called quadrants. In the first quadrant all the trigonometric ratios are positive.
Example.2 If cot A , find the value of 3 cos A + 4 sin A, where A is in the first quadrant.
Example.3 Find the value of
= 1 + 1 - 1 = 1
Table: Values of trigonometric Ratio for some special angles.
➢ Sine Rule
➢ Cosine Rule
➢ Area of Triangle