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Mathematics LibreTexts

2.1: Continuity

  • Page ID
    143115
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    1. Sketch the graph of a continuous function that passes through the points \((-3, -1)\), \((-1, 2)\), \((0, -1)\), and \((2, 3)\).
       
    2. Sketch the graph of a function that has a removable discontinuity at \(x = 1\).
       
    3. Sketch the graph of a function that has a jump discontinuity at \(x = 2\).
       
    4. Sketch the graph of a function that has an infinite discontinuity at \(x = -1\).
       
    5. Sketch the graph of the function \(f(x) = x^2 - 1\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    6. Sketch the graph of the function \(f(x) = \dfrac{1}{x}\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    7. Sketch the graph of the function \(g(x) = \dfrac{1}{x^2 - 1}\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    8. Sketch the graph of the function \(h(x) = \dfrac{1}{x^2 + 1}\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    9. Sketch the graph of the function \(f(x) = \dfrac{x^2}{x}\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    10. Sketch the graph of the function \(g(x) = \dfrac{x+2}{x^2-x-6}\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    11. Sketch the graph of the function \(h(x) = \tan(x)\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    12. Sketch the graph of the function \(f(x) = \dfrac{|x|}{x}\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    13. Sketch the graph of the function \(g(x) = \dfrac{1}{\sqrt{x}}\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    14. Sketch the graph of the function \(h(x) = \sqrt{x^2-1}\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    15. Sketch the graph of the function
      \[f(x) = \left\{\begin{align*}
      & x^2, & x \neq -1, \\
      & 2, & x = -1.
      \end{align*}\right.\]
      For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    16. Sketch the graph of the function
      \[g(x) = \left\{\begin{align*}
      & -x, & x < 0, \\
      & \sqrt{x}, & x \ge 0.
      \end{align*}\right.\]
      For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    17. Sketch the graph of the function
      \[h(x) = \left\{\begin{align*}
      & 2^x, & x \le 0, \\
      & \frac{1}{x}, & x > 0.
      \end{align*}\right.\]
      For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    18. Sketch the graph of the function
      \[h(x) = \left\{\begin{align*}
      & \frac{1}{x^2}, & x < 2, \\
      & \pi, & x = 2, \\
      & 2x-5, & x > 2.
      \end{align*}\right.\]
      For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    19. Sketch the graph of the function \(f(x) = \sin\left(\dfrac{1}{x}\right)\). For what values of \(x\) is the function continuous? For what values of \(x\) is the function discontinuous? Classify any discontinuity as removable, jump, infinite, or other.
       
    20. Consider the function \(g(x) = x^2\), and recall that \(\sqrt{2} = 1.414213562\ldots\). The \(x\)-values in the table below approximate \(x = \sqrt{2}\). The \(x\)-values on the left side of the table approach \(\sqrt{2}\) from the left; the \(x\)-values on the right right side of the table approach \(\sqrt{2}\) from the right. Use a calculator to complete the table by evaluating the function at these values. Do the function values give a good approximation of \(g(\sqrt{2})\)? Why or why not?
       
      \(x\) \(g(x)\)   \(x\) \(g(x)\)
      1.41     1.42  
      1.414     1.415  
      1.4142     1.4143  

       

    21. Consider the function \(h(x) = \dfrac{x-1}{x^2-3x+2}\), and recall that \(\sqrt{2} = 1.414213562\ldots\). The \(x\)-values in the table below approximate \(x = \sqrt{2}\). The \(x\)-values on the left side of the table approach \(\sqrt{2}\) from the left; the \(x\)-values on the right right side of the table approach \(\sqrt{2}\) from the right. Use a calculator to complete the table by evaluating the function at these values. Do the function values give a good approximation of \(h(\sqrt{2})\)? Why or why not?
       
      \(x\) \(h(x)\)   \(x\) \(h(x)\)
      1.41     1.42  
      1.414     1.415  
      1.4142     1.4143  

       

    22. Consider the function \(f(x) = \dfrac{|x^2 - 2|}{x^2 - 2}\), and recall that \(\sqrt{2} = 1.414213562\ldots\). The \(x\)-values in the table below approximate \(x = \sqrt{2}\). The \(x\)-values on the left side of the table approach \(\sqrt{2}\) from the left; the \(x\)-values on the right right side of the table approach \(\sqrt{2}\) from the right. Use a calculator to complete the table by evaluating the function at these values. Do the function values give a good approximation of \(f(\sqrt{2})\)? Why or why not?
       
      \(x\) \(f(x)\)   \(x\) \(f(x)\)
      1.41     1.42  
      1.414     1.415  
      1.4142     1.4143  

       

    23. Consider the function \(g(x) = \dfrac{1}{x^2 - 2}\), and recall that \(\sqrt{2} = 1.414213562\ldots\). The \(x\)-values in the table below approximate \(x = \sqrt{2}\). The \(x\)-values on the left side of the table approach \(\sqrt{2}\) from the left; the \(x\)-values on the right right side of the table approach \(\sqrt{2}\) from the right. Use a calculator to complete the table by evaluating the function at these values. Do the function values give a good approximation of \(g(\sqrt{2})\)? Why or why not?
       
      \(x\) \(g(x)\)   \(x\) \(g(x)\)
      1.41     1.42  
      1.414     1.415  
      1.4142     1.4143  

       

    24. Consider the function \(h(x) = \dfrac{x^2 - 2}{x^4 - 4}\), and recall that \(\sqrt{2} = 1.414213562\ldots\). The \(x\)-values in the table below approximate \(x = \sqrt{2}\). The \(x\)-values on the left side of the table approach \(\sqrt{2}\) from the left; the \(x\)-values on the right right side of the table approach \(\sqrt{2}\) from the right. Use a calculator to complete the table by evaluating the function at these values. Do the function values give a good approximation of \(h(\sqrt{2})\)? Why or why not?
       
      \(x\) \(h(x)\)   \(x\) \(h(x)\)
      1.41     1.42  
      1.414     1.415  
      1.4142     1.4143  

       

    25. Consider the function \(f(x) = \dfrac{1}{x^2} - 2\). Evaluate \(f(1)\) and \(f(2)\). Does the Intermediate Value Theorem guarantee that the function has a zero on the interval \((1, 2)\)? Why or why not? Confirm your answer using a graphing calculator.
       

    26. Consider the function \(g(x) = \dfrac{1}{x^2 - 2}\). Evaluate \(g(1)\) and \(g(2)\). Does the Intermediate Value Theorem guarantee that the function has a zero on the interval \((1, 2)\)? Why or why not? Confirm your answer using a graphing calculator.


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