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 * **Aim: What are the co-functions and the quotient identities?**

In this lesson we will learn the co-functions and the quotient identities. These will help you with later trig problems such as proving and solving. It is very important that you memorize these as they will not be on the Alg2/Trig Regents refernece sheet. The more familiar you are with them, the easier it will be to work with them.


 * Before you begin watching these videos, here are some questions you need to copy down to answer in your notebooks as you watch the videos:
 * 1) What are the co-functions?
 * 2) What are their relationships.


 * **Videos**

[|Video 1]

[|Video 2]


 * **Here are the quotient identities and the reciprocal identities:** copies these down into your notebooks. As I said before these will not be on the Regents reference sheet, but you will have a better understanding of them if you are familiar with them. So, PRACTICE!!!

tan a = (sin a)/(cos a)
 * __Quotient Identites__**

cot a = (cos a)/(sin a)

sin a = 1/(csc a) cos a = 1/(sec a) tan a = 1/(cot a) csc a = 1/(sin a) sec a = 1/(cos a) cot a = 1/(tan a)
 * __Reciprocal Identites:__ There are six of these. Can you find a way that you might need to remember only 3?**


 * **Homework:** Complete all but #2

[|8.4_Cofunctions.JPG]

[|A-8.4_Cofunctions.JPG]
 * Answers


 * **Journal entry:** The words cotangent, cosecant, and cosine all begin with the prefix "co". Explain a reason for this.