Answer: see proof below
<u>Step-by-step explanation:</u>
Use the Sum & Difference Identity: cos (A + B) = cos A · cos B - sin A · sin B
Recall the following from Unit Circle: cos (π/2) = 0, sin (π/2) = 1
cos (π) = -1, sin (π) = 0
Use the Quotient Identity: 
<u>Proof LHS → RHS:</u>




Quotient: tan x
LHS = RHS 
It would be 7 because -3 times 5
Answer:
60
Step-by-step explanation:
rate of change of graph,df(x)/dx
=(120-0)/(3-1)=60
$52.95 - $2.50 = $50.45
$50.45 divided by 5 (number of people) = $10.09 per person