Verifying Trigonometric Identities - Watch video (Trigonometry)

Trigonometry: Verifying Trigonometric Identities

This is a free lesson from our course in Trigonometry


	In this lesson you'll learn with the help of several examples, practice questions with solution and video explanation that how to use trigonometric identities to simplify trigonometric expressions. A trigonometric identity is different from a trigonometric expression in that an identity will have an equal (=) sign in it. To verify an identity means to make sure that the equation is true by setting both sides equal to one another. There is no set method that can be applied to verifying identities. (More text below video...)

Other useful lessons:

Pythagorean Trigonometric Identity

Getting started - Trigonometric identities

(Continued from above) Few ways to start based on the identity are used often:

Start with one side of the equation and see if you can change to other side using algebra steps (more common in use).
You may start with an identity that is true and do the same thing to both sides of it to get the identity you want to verify.
Change to sines and cosines, if you can, to recognize in the equation.

For Example: 1 / cot(t) = sin(t) / cos(t)
and you know 1/cot(t)= tan(t) ,so
tan(t) = sin(t) / cos(t)
also, tan(t) is the same as sint(t)/cos(t) and therefore can be rewritten as
sin(t) / cos(t) = sin(t) / cos(t)
Hence, identity is verified.

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