---
metadata:
    display_name: Math Expression Input
    markdown: !!null
data: |
  <problem>
  <p>
  In math expression input problems, learners enter text that represents a
  mathematical expression into a field, and text is converted to a symbolic
  expression that appears below that field. You can refer learners to 
  <a href="http://edx.readthedocs.org/projects/edx-guide-for-students/en/latest/SFD_mathformatting.html" target="_blank">
  Entering Mathematical and Scientific Expressions</a> in the <i>edX Guide for
  Students</i> for information about how to enter text into the field.
  </p>
  <p>
  Math expression problems can include unknown variables and relatively
  complicated symbolic expressions. The grader uses a numerical sampling to
  determine whether the student’s response matches your math expression, to a
  specified numerical tolerance. You must specify the allowed variables in the
  expression as well as the range of values for each variable.
  </p>
  <p>
  To create these problems, you use MathJax to change your plain text into
  "beautiful math." For more information about how to use MathJax in Studio,
  see <a href="http://edx.readthedocs.org/projects/edx-partner-course-staff/en/latest/exercises_tools/mathjax.html" target="_blank">
  A Brief Introduction to MathJax in Studio</a> in <i>Building and Running an edx
  Course</i>.  
  </p>
  <p>When you add the problem, be sure to select <strong>Settings</strong> 
  to specify a <strong>Display Name</strong> and other values that apply.</p>
  <p>You can use the following example problems as models.</p>
  
  <p>Write an expression for the product of \( R_1\), \( R_2\), and
  the inverse of \( R_3\) .</p>
  <formularesponse type="ci" samples="R_1,R_2,R_3@1,2,3:3,4,5#10" answer="$VoVi">
    <responseparam type="tolerance" default="0.00001"/>
    <formulaequationinput size="40" label="Enter the equation"/>
  </formularesponse>

  <script type="loncapa/python">
  VoVi = "(R_1*R_2)/R_3"
  </script>

  <p>Let \( x\) be a variable, and let \( n\) be an arbitrary constant.
  What is the derivative of \( x^n\)?</p>
  
  <script type="loncapa/python">
  derivative = "n*x^(n-1)"
  </script>

  <formularesponse type="ci" samples="x,n@1,2:3,4#10" answer="$derivative">
    <responseparam type="tolerance" default="0.00001"/>
    <formulaequationinput size="40"  label="Enter the equation"/>
  </formularesponse>

  </problem>
