Krishna
0

Step 1:  Assume any right angle triangle

EXAMPLE:

Step 2:  Make the angle \theta = 0

NOTE:  The angle A decreases, the height of C from AB ray decreases and foot B is shifted from B to B_1 \text{ and } B_2 and gradually when the angle becomes zero, height (i.e. opposite side of the angle) will also become zero (0) and adjacent side would be equal to AC.

•   BC = 0................................(1)
•   AB = AC ............................(2)

Step 3: Recall the trigonometric ratios and find the values at angle 0\degree

EXAMPLE:  (i)   \sin 0\degree = \frac{opposite}{hypotenuse}

\sin 0\degree = \frac{BC}{AC} = \frac{0}{AC} [since Equation (1)]

Therefore, \sin 0\degree = 0

\cos0\degree=\frac{AB}{AC}=\frac{AC}{AC} [since equation (2)]

Therefore, \cos 0\degree = 1