Lesson 11
Making a Model for Data
Let’s model with functions.
Problem 1
A line \(\ell\) is defined by the equation \(f(x) = 2x - 3\).
- Line \(m\) is the same as line \(l\), but shifted 1 unit right. What is an equation for a function \(g\) that defines the line \(m\)?
- Line \(n\) is the same as line \(m\), but shifted 2 units up. What is an equation for a function \(h\) that defines the line \(n\)?
- What is the relationship between \(f\) and \(h\)?
Problem 2
The functions \(g\) and \(f\) are related by the equation \(g(x) = f(\text-x) + 3\). Which sequence of transformations will take the graph of \(f\) to the graph of \(g\)?
Problem 3
The function \(f\) is linear. Can \(f\) be an odd function? Explain how you know
Problem 4
Technology required. The function \(f\) is given by \(f(x) = x^3 + 1\). Kiran says that \(f\) is odd because \((\text-x)^3 = \text-x^3\).
- Do you agree with Kiran? Explain your reasoning.
- Graph \(f\), and use the graph to decide whether or not \(f\) is an odd function.
Problem 5
Here are graphs of three functions \(f\), \(g\), and \(h\) given by \(f(x) = (x-1)^2\), \(g(x) = 2(x-1)^2\) and \(h(x) = 3(x-1)^2\).
Identify which function matches each graph. Explain how you know.
Problem 6
Technology required. Describe how to transform the graph of \(f(x) = x^2\) into the graph of \(g(x) = 4(3x-1)^2 + 5\). Check your response by graphing \(f\) and \(g\).
Problem 7
Let \(p\) be the price of a T-shirt, in dollars. A company expects to sell \(f(p)\) T-shirts a day where \(f(p) = 50 - 4p\). Write a function \(r\) giving the total revenue received in a day.
Problem 8
A population of 80 single-celled organisms is tripling every hour. The population as a function of hours since it is measured, \(h\), can be represented by \(g(h) =80 \boldcdot 3^h\).
Which equation represents the population 10 minutes after it is measured?
\(g(10) =80 \boldcdot 3^{10}\)
\(g(0.1) =80 \boldcdot 3^{0.1}\)
\(g(\frac16) =80 \boldcdot 3^\frac16\)
\(g(6) =80 \boldcdot 3^6\)