Krishna
0

Step 1:  Note down the given important points

            EXAMPLE:  \cos 7A = \sin (A - 6\degree)

                                 7A is an acute angle


Step 2: Write the equivalent complementary angle

            NOTE:   \cos \theta = \sin (90\degree - \theta)

            EXAMPLE:   \cos 7A = \sin (90\degree - 7A) ........(1)


Step 3:  Substitute the calculated value and simplify

               EXAMPLE:   \sin (90\degree - 7A) = \sin (A - 6\degree)

                                   90\degree - 7A = A - 6\degree

                                   8A = 96\degree

                                   A =\frac{96}{8}

                                   A = 12\degree