A plane flies 720 miles with the wind in 3 hours. The return trip against the wind takes 4 hours. What is the speed of the wind
1 answer:
You might be interested in
Answer:
See below.
Step-by-step explanation:
First, use the co-function identity:
We can turn the second term into cosine:
Substitute:
Now, use the sum to product formulas. We will use the following:
Substitute:
Use the even-odd identity:
Therefore:
Replace the second term with the original term:
Proof complete.
