Krishna
0

Step 1: Identify the known parts of the problem.

               NOTE:   \sin A = \cos B

                            Prove:  A  + B  = 90\degree

Step 2:  Make a use of the trigonometric ratios of complimentary angles.

             NOTE:  We know \cos B = \sin (90\degree - B)............(1)

            

Step 3:  Prove the required equation

            EXAMPLE: \sin A = \cos B

                               \sin A = \sin (90\degree - B) [ \because Equation (1)]

                             Cancel the \sin on both sides

                               A = 90\degree - B

                               A + = 90\degree