1. The function f is decreasing and is defined for all real numbers. The table gives values for f(x) at selected values of x.
| x | -2 | -1 | 0 | 1 | 2 |
|---|---:|---:|---:|---:|---:|
| f(x) | 14 | 7 | 3.5 | 1.75 | 0.875 |
The function g is given by g(x) = −0.167x³ + x² − 1.834.
A.
i. The function h is defined by h(x) = (g ∘ f)(x) = g(f(x)). Find the value of h(1) as a decimal approximation, or indicate that it is not defined. Show the work that leads to your answer.
ii. Find the value of f⁻¹(3.5), or indicate that it is not defined.
B.
i. Find all values of x, as decimal approximations, for which g(x) = 0, or indicate that there are no such values.
ii. Determine the end behavior of g as x increases without bound. Express your answer using the mathematical notation of a limit.
C.
i. Based on the table, which of the following function types best models function f: linear, quadratic, exponential, or logarithmic?
ii. Give a reason for your answer in part C (i) based on the relationship between the change in the output values of f and the change in the input values of f. Refer to the values in the table in your reasoning.
6.0000 pts
None (top-level)
Yes
Rubric Criteria (6)
A1Computes h(1)=g(f(1))=g(1.75) as the decimal approximation 0.333, with supporting work showing f(1), g(1.75), or 1.75.
1.0000pts
A2States that f^{-1}(3.5)=0.
1.0000pts
B1Lists all three zeros of g as the decimal approximations x=-1.233, x=1.578, and x=5.643; no supporting work is required.
1.0000pts
B2States the end behavior using a complete limit statement containing lim, x→∞, the function g, and -∞; for example, lim_{x→∞}g(x)=-∞. Any additional complete limit statement must also be correct.
1.0000pts
C1Identifies exponential as the function type that best models f, without listing an incorrect function type.
1.0000pts
C2Explains the exponential model by referencing the table's equal-length input intervals and showing that successive output values have ratio 0.5 for more than one pair, such as f(n+1)/f(n)=0.5 or successive outputs decreasing proportionately by a factor of 0.5.
1.0000pts
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