SIn and Cos?

Question

Think of two complementary angles and list the sine and cosine for each.
Complementary angles      ° and      °
sin      ° =       cos      ° =      ?

sin      ° =       cos      ° =      

How does the value of sine and cosine of complementary angles relate?      

Explain in your words why this relationship of sine and cosine holds for complementary angles.    

Answer 1

Carolyn, this deals with cofunctions, of which sine and cosine are one pair. A function of an angle is equal to the cofunction of its conpliment.

 

What?? Remember that complimentary angles add up to 90 degrees. All that stuff at the beginning says that the sine of one is the cosine of the other, and vice versa.

 

sin(50°) = cos(40°)

 

Hope this helps!