Module 5: Trigonometry Applications and Identities

 

There are many different ways of writing the proof of an identity correctly; however, the proof style used in this lesson always ends with the left side the same as the right side. Two possible proofs are shown in Example Proof 1A and Example Proof 1B. Compare these proofs to your proof.

 

 
This play button opens Example Proof 1A.
 
This play button opens Example Proof 1B.

Self-Check 2


textbook

Complete question 2 on page 314 of the textbook. Answer

 

 

The next identity has double angles in it. Complete Try This 4 with a group if possible, but alone if necessary.


Try This 4

 

Consider the identity .

  1. Which side of the equation do you feel is more complex?
  2. Which strategies do you think may be used to prove the identity?

  3. Try using one or more of the strategies you discussed in question 2 to prove the identity.

  4. Compare your proof to a partner’s.

  5. Compare your proof from Try This 4 to Example Proof 2.

     
    This play button opens Example Proof 2.

course folder Save your responses and a record of your discussion in your course folder.

 

Remember, there are many correct ways to write a proof.

Review the list of strategies provided just before Try This 3.