Answer: see proof below
<u>Step-by-step explanation:</u>
Given: cos 330 =
Use the Double-Angle Identity: cos 2A = 2 cos² A - 1
Proof LHS → RHS:
LHS cos 165
Double-Angle: cos (2 · 165) = 2 cos² 165 - 1
⇒ cos 330 = 2 cos² 165 - 1
⇒ 2 cos² 165 = cos 330 + 1
Given:
Divide by 2:
Square root:
Scratchwork:
Since cos 165 is in the 2nd Quadrant, the sign is NEGATIVE
LHS = RHS
Ok. First you have to find the unit rate. Since you can buy 9 packages of grapes for $24, then you can get 1 grape package for $2.6667. If you have $8, you can buy 3 packages of grapes.
Answer:
$607.75
Step-by-step explanation:
As a first approximation, compound interest will be slightly higher than simple interest for a relatively short time period. Here simple interest at 5% for 4 years will add 4×5% = 20% to the value, adding about $100 to the initial $500 value. That is, we expect the value in 4 years to be slightly more than $600.
The appropriate answer choice is $607.75.
_____
The actual amount can be calculated using the multiplier 1.05 for each of the 4 years, or 1.05^4 ≈ 1.21550625 for the entire period. Then the predicted item value is ...
$500 × 1.21550625 = $607.753125 ≈ $607.75