title: calculate area between four curves using matlab
body: <h2>calculate area between four curves using matlab</h2>
  <p>Hi everyone,
  I have four curves in matlab. The two of them are calculated through the following formulas
  y=x and
  y=1-x
  The other two curves are calculated through a number (13) of values.
  All of them shaped an area with their intersection points (ABCD) that I want to calculate.
  I have to use trapz and if yes how?</p>
  <p>and a second question. How can I fill in with a new color the spesific area (ABCD)?</p>
  <p>Thank you in advance</p>