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Thursday, October 25, 2012

Proving Basic Trigonometric Identity

Category: Trigonometry, Plane Geometry

"Published in Newark, California, USA"

Prove that:

    
Solution:
 
Let's consider the right triangle
 
Photo by Math Principles in Everyday life
 
We know that 

and 

From Pythagorean Theorem,


divide both sides of the equation by c2, we have

                                 or
Therefore,