Table and graph of a function
Before analysing a function with analytical tools, you need to know how to sketch it: choose the values of $x$ carefully, calculate their images and join the points sensibly, knowing which regions need more points than others.
Table of values: which points to choose
Given the linear function $f(x) = 2x - 3$: a) Complete a table of values for $x \in \{-2, 0, 1, 3\}$. b) Draw the graph of the function in the Cartesian plane using the…
Given the linear function $f(x) = 2x - 3$:
- a) Complete a table of values for $x \in \{-2, 0, 1, 3\}$.
- b) Draw the graph of the function in the Cartesian plane using the points obtained.
You can do it on paper and send a photo with your answer.
Consider the quadratic function $f(x) = x^2 - 4$: a) Calculate the images for $x = -3, -2, 0, 2, 3$ and organise the results in a table. b) Draw the graph of the…
Consider the quadratic function $f(x) = x^2 - 4$:
- a) Calculate the images for $x = -3, -2, 0, 2, 3$ and organise the results in a table.
- b) Draw the graph of the function and identify the coordinates of its vertex.
You can do it on paper and send a photo with your answer.
Rational and radical functions: points near the excluded value
In a rational function, the interesting values are near the value that makes the denominator zero, not far from it; in a radical function, the domain starts exactly where the radicand becomes zero.
Given the radical function $f(x) = \sqrt{x+2}$: a) Determine its domain analytically. b) Complete a table of values for $x \in \{-2, -1, 2, 7\}$ and use it to sketch the…
Given the radical function $f(x) = \sqrt{x+2}$:
- a) Determine its domain analytically.
- b) Complete a table of values for $x \in \{-2, -1, 2, 7\}$ and use it to sketch the graph.
Given the rational function $f(x) = \frac{4}{x-2}$: a) Determine its domain. b) Construct a table of values evaluating the function at points close to $x = 2$ from the…
Given the rational function $f(x) = \frac{4}{x-2}$:
- a) Determine its domain.
- b) Construct a table of values evaluating the function at points close to $x = 2$ from the left and from the right ($x = 1,9; 1,99; 2,1; 2,01$).
- c) Based on the results obtained, what graphical feature does the function display at $x = 2$?
You can do it on paper and send a photo with your answer.
Piecewise functions: continuity at the junction
Given the piecewise function: $f(x) = \begin{cases} -x + 2 & \text{if } x < 1 \\ 2x - 1 & \text{if } x \ge 1 \end{cases}$ a) Construct a table of values by evaluating…
Given the piecewise function:
$f(x) = \begin{cases} -x + 2 & \text{if } x < 1 \\ 2x - 1 & \text{if } x \ge 1 \end{cases}$
- a) Construct a table of values by evaluating the function at $x = -2; 0; 0,99; 1; 2; 3$.
- b) Draw the graph of the function and state whether it is continuous at $x = 1$.
You can do it on paper and send a photo with your answer.
Given the piecewise function depending on a parameter $k$: $f(x) = \begin{cases} x^2 - k & \text{if } x < 2 \\ 2x + 1 & \text{if } x \ge 2 \end{cases}$ a) Find the value…
Given the piecewise function depending on a parameter $k$:
$f(x) = \begin{cases} x^2 - k & \text{if } x < 2 \\ 2x + 1 & \text{if } x \ge 2 \end{cases}$
- a) Find the value of $k$ so that the two branches of the function "connect" at the point $x = 2$ (that is, so that the function is continuous).
- b) Using the value of $k$ found, construct a table of values in the interval $[0, 4]$ and sketch the graph of the function.
You can do it on paper and send a photo with your answer.
Reading a graph: trends and asymptotes
You do not always construct the graph: you also have to read it when it is already drawn, extracting information without needing the formula.
The following graph shows the evolution of the temperature $T$ (in $^\circ\text{C}$) of a cup of coffee as a function of time $t$ (in minutes) since it is served. From…
The following graph shows the evolution of the temperature $T$ (in $^\circ\text{C}$) of a cup of coffee as a function of time $t$ (in minutes) since it is served.
From the graph:
- a) State the initial temperature of the coffee.
- b) What value does the temperature approach as a large amount of time elapses? What physical meaning does the horizontal asymptote have?
- c) Is the function increasing or decreasing? Justify your answer.
Observe the following graph of a rational function of the form $f(x) = \frac{ax+b}{cx+d}$: From the information provided by the graph (asymptotes and axis intercepts):…
Observe the following graph of a rational function of the form $f(x) = \frac{ax+b}{cx+d}$:
From the information provided by the graph (asymptotes and axis intercepts):
- a) Determine the domain and range of the function.
- b) Deduce the algebraic expression of the function $f(x)$.