1. The first option is represented by a linear function, ∴ y = 50x + 150. The y intercept here is 150, as the first week is 200 dollars, not the 0th week. 200 - 50 = 150.
Given the domain here is 1 - 6 (6 weeks) we can plug in x as 1,2,3 etc and solve for y, completing the table.
Option A :
Week | 1 | 2 | 3 | 4 | 5 | 6 |
Amount Paid | 200 | 250 | 300 | 350 | 400 | 450 |
And for option b we have an exponential function. 1 + 10% = 1 + 0.1 = 1.1. Therefore we have the function ∴ y = 200( 1.1 )^x-1 that models this situation. Remember that we have " x - 1 " as the exponent rather than x, as the first week begins with 200 dollars, not the 0th week.
That gives us the following table,
Option B :
Week | 1 | 2 | 3 | 4 | 5 | 6 |
Amount Paid | 200 | 220 | 242 | 266.2 | 292.82 | 322.102 |
2. (a) We already calculated the " iterative rules " for each sequence in the first part. For your explanation on that behalf, just include the explanation above. Rule of Option A : y = 50x + 150. Rule of Option B : [tex]y = 200( 1.1 )^{x-1}[/tex].
(b) Let's take an example week and substitute into our equations to help clarify our friend's doubt. Say week 2...
y = 50(2) + 150 = 100 + 150 = 250 ✓
y = 200( 1.1 )^2-1 = 200( 1.1 )^1 = 200( 1.1 ) = 220 ✓
3. (a) A function is an equation that represents the relation between x and y, which is exactly the purpose of the rules y = 50x + 150, and y = 200( 1.1 )^x-1.
(b) I disagree with my friend. These particular examples do have y - intercepts, but just because a rule is a function, doesn't make it have a y - intercept. There are some exceptions, such as y = 1 / x.
(c) An input such as 18.5 is meaningless, as x represents the weeks. An employer doesn't provide the payments at half weeks.
4. Let's substitute 20 as x,
y = 50 * 20 + 150 = 1,000 + 150 = $1,150
y = 200( 1.1 )^x-1 = 200( 1.1 )^20-1 = 200( 1.1 )^19 = $1,223.1818
The first payment option will provide the greatest total income.
