Why is the cosine of an obtuse angle negative?
1 Answer
Nov 22, 2015
Draw the cosine function between 0 and 180 degrees and you will learn why angles
Explanation:
Here is the graph of cosine:
As you can see, once the cosine function is greater than 90 degrees, the value becomes negative .
Between 0 and 90 degrees , cosine is positive .
hope that helped