Express the Tangent of A in terms of the Cosine of A.

 

Use the trigonometric identities to convert between trigonometric functions.

 

Tangent A =   

 

 

             Sine A

Tangent A = ----------

             Cosine A

 

    but since sine A  = Square root of (1 - Cosine2 A), which can also be written as (1 - Cosine2 A)1/2 we get

 

            (1 - Cosine2 A)1/2

Tangent A = ----------------

              Cosine A

 

This can be useful if for some reason you have a cosine table but do not have a tangent table.  You can then determine the value of the tangent even without the tangent table.

 

The trigonometric identities used above are as follows:

 

                                  Sine A

Tangent A = (Sine A)/(Cosine A)=----------

                                 Cosine A

Sine2 + Cosine2 = 1