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

                                

                                  (ii)   \cos 0\degree = \frac{adjacent}{hypotenuse}

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

                                       Therefore, \cos 0\degree = 1


                                 (iii)   \tan 0\degree = \frac{opposite}{adjacent}

                                          \tan 0\degree = \frac{BC}{AB} = \frac{0}{AB} [since Equation (1)]

                                         Therefore, \tan 0\degree = 0

                                                    or

                                            \tan 0\degree = \frac{\sin 0\degree}{\cos 0\degree}

                                             \tan 0\degree = \frac{0}{1} = 0