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Create Math Graph using Matlab?

  1. Aug 27, 2015 #1
    How do I create a graph of y = x^2 + x + 1 in Matlab?

    Where I could create the above math graph in Matlab (please see below image)?

    Matlab.png
     
  2. jcsd
  3. Aug 27, 2015 #2
    Type in command window the following:

    Code (Text):

    x=[-5:0.2:5];
    y=x.*x+2*x+1;
    plot(x,y);
     
     
  4. Aug 27, 2015 #3
    What is the meaning of below code?

    x=[-5:0.2:5];

    Also, is y=x.*x+2*x+1; mean ##y = x^2 + 2x + 1##?

    If so, then there is a mistake with the above code.

    It should be ##y = x^2 + x + 1##.

    What is the correct code of ##y = x^2 + x + 1## in Matlab?
     
  5. Aug 27, 2015 #4
    You can remove the factor of 2, I put it by mistake.

    Anyway, you would better start a free tour of Matlab documentation.
     
  6. Aug 28, 2015 #5
    Thank you, but, the documentation doesn't help.

    Can someone please tell me the order of creating math graph in Matlab with explanation?
     
  7. Aug 28, 2015 #6

    DrClaude

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    Staff: Mentor

  8. Aug 28, 2015 #7

    RUber

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    Homework Helper

    I agree that taking the MATLAB tutorials would be helpful for you. These are basic syntax questions.

    This command tells matlab to create a vector called "x" with initial value -5 and final value 5 with intermediate values spaced .02 units apart.
    You can adjust your initial and final values as well as your step size as you see fit.
    y = x . ^2 + x + 1;
    will create a vector called "y" which is the same size as x and for every value in x, it will compute x^2 + x +1. Notice the dot before the exponent: .^2 means to return the square of each element...as opposed to ^2 which tries to square the vector using matrix multiplication.

    plot(x,y) is the simplest graphing option and requires that the two vectors be the same length.
     
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