Textbook ExpertVerified Tutor
24 Nov 2021
Given information
The subtraction formula for cosine is:
The given figure is:
Step-by-step explanation
Step 1.
- The law of cosines states that where , and are the lengths of sides of triangle and is the angle between the sides with lengths and
- From the figure, in the triangle , it can be noticed that:
- Substitute the values of , , and in the law of cosines.