Simple Expressions

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• Questions?
• Variables and Expressions (Lesson 1)
  • Polynomial
    • Typical solution
      

      x = 3
      2 * x ^ 3 - x ^ 2 - 7 * x + 12

    • A different way to solve this—a different algorithm
      

      (( 2 * x - 1) * x) - 7) * x + 12

      • Horner’s rule
    • Algorithm quality
      • Clarity
      • Efficiency
    • Testing matters
      • Do it with several inputs picked so that you know the answers your code should produce
    • Yet another way to solve this problem (though it uses Matlab features a litle ahead of where we are)
      • polyval function
  • Hypotenuse
    • Typical solution
      

      x = 78
      y = 891
      sqrt( x^2 + y^2 )

    • Or hypot( x, y )
    • Symbolic math
      

      syms c
      solve …

      • Very interesting part of Matlab, but can also be very confusing because it puts Matlab into a mode where it treats some variables as programming language variables (i.e., containers for values) and others as mathematical variables (i.e., abstract symbols for not-completely-known values)
• Next
  • Continue variables and expressions lesson, especially quadratic equation part
  • Watch “What Is an Algorithm” video lecture at https://cloud.ensemblevideo.com/app/sites/index.aspx?destinationID=IlO-D-b-vUWVkAsj2Is5Zg

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