Let's answer each question step by step:
Question 2 A)
From the table:
Minutes | Messages Sent
0 | 0
1 | 3
2 | 9
3 | 27
4 | 81
We are looking for the point that represents the third term in the geometric sequence. The third term in the Messages Sent column corresponds to 27, which occurs at 3 minutes.
Therefore, the point to be graphed is (3, 27).
Answer: (3, 27)
Question 3 A)
The geometric sequence given is 40, 160, 640, ...
To find an exponential function, we can look for a common ratio.
- \(160 / 40 = 4\)
- \(640 / 160 = 4\)
Thus, the common ratio is 4.
As a geometric sequence, we can express it in the form:
- \( a_n = a \cdot r^{(n-1)} \)
Where:
- \( a \) = first term (40)
- \( r \) = common ratio (4)
Thus the function becomes:
- \( a_n = 40 \cdot 4^{(n-1)} \)
Answer: \( a_n = 40(4)^{n-1} \)
Question 4 A)
The car's value decreases by 15% each year, meaning it retains 85% of its value. The formula for the value of the car after \( t \) years can be given by:
\[ V(t) = V_0 \cdot (1 - r)^t \] Where:
- \( V_0 = 24,500 \)
- \( r = 0.15 \)
- \( t = 5 \) years
Substituting these values:
\[ V(5) = 24500 \cdot (0.85)^5 \]
Calculating it:
-
Calculate \( (0.85)^5 \): \[ (0.85)^5 \approx 0.4437 \]
-
Multiply \( 24,500 \) by \( 0.4437 \): \[ 24500 \cdot 0.4437 \approx 10870.78 \]
Answer: $10,870.78
Question 5 A)
Given the geometric sequence 6, 18, 54, ..., we first identify the common ratio:
- \( 18 / 6 = 3 \)
- \( 54 / 18 = 3 \)
The common ratio is 3, and the first term is 6.
The general form for the nth term (function) is:
- \( f(x) = a \cdot r^x \)
Where:
- \( a = 6 \)
- \( r = 3 \)
Thus:
- \( f(x) = 6 \cdot 3^x \)
We can express it in terms of \( n - 1 \):
So, the correct expression is:
- \( f(x) = 6(3)^{x-1} \)
Answer: \( f(x) = 6(3)^{x-1} \)
Summary of Answers:
- (3, 27)
- \( a_n = 40(4)^{n-1} \)
- $10,870.78
- \( f(x) = 6(3)^{x-1} \)