SOLUTION: Trigonometry Identities Prove the identity is true 1/cosx - cosx = sinx tanx

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Question 95110: Trigonometry Identities
Prove the identity is true

1/cosx - cosx = sinx tanx

Answer by bucky(2189)   (Show Source): You can put this solution on YOUR website!
Here's one way. You will need to use the two identities:
.

and

.
Given:
.

.
substitute for tan(x) to get:
.

.
This substitution changes the right side and the equation becomes:
.

.
Get rid of the denominator by multiplying all the terms on both sides to get:
.

.
Cancel the in the denominator with the corresponding in the numerator:
.

.
and this reduces the equation to:
.

.
Add to both sides to get rid of the on the left side. This
changes the equation to:
.

.
This is in the form of a trigonometric identity that you are probably familiar with already.
Since you have now worked the original given equation into a form known to be true, you
have successfully proved that the original given equation is true.
.
Hope that this helps you to understand the problem.
.

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