5.4 Sum and Difference Identities for Sine and Tangent

 

 

Sine of a Sum or Difference

 

 

Tangent of a Sum or Difference

 

 

Example

Find the exact value of each expression

 

 

 

 

 

 

 

 

 

Write each function as an expression involving functions of θ.

 

 

 

 


 

 

 

 

 

 

 

 

 

Finding Function Values and the Quadrant of A + B

Example

Suppose that A and B are angles in standard position, with

 

Find each of the following:

 

a) b)

 

 

 

 

 

 

 

 

 

c) the quadrant of A B

 


Verifying An Identity using Sum and Difference Identities

Example

Verify that the equation is an identity.