Answer: see proof below
<u>Step-by-step explanation:</u>
Use the Sum & Difference Identity: tan (A - B) = (tanA - tanB)/(1 + tanA tanB)
Use the Half-Angle Identity: tan (A/2) = (1 - cosA)/(sinA)
Use the Unit Circle to evaluate tan (π/4) = 1
Use Pythagorean Identity: cos²A + sin²A = 1
<u>Proof LHS → RHS</u>
= cos A
LHS = RHS: cos A = cos A 
<span>6 servings ... 1/2 cup of butter
8 servings .... x cup of butter
We would like to know what is the value of the x.
</span>6 * x = 8 * 1/2<span>
6 * x = 4 /6
x = 4/6
x = 2/3
Result: Nancy needs</span> 2/3 cup of butter for 8 servings.
The mean is <span>29.25 but you need to round it so it would be 30 hope it helps <3</span>
3 laps in 2.5 minutes
1 lap = 2.5/3 minute
20 laps = (2.5/3)*20 = 16.67
20 laps ≈ 16.67 minutes
