14.10: Plotting Symbolic Expressions

Fundamentals of MATLAB Programming · LibreTexts

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    From LibreTexts, under CC BY-NC-SA, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    To plot symbolic expressions, use fplot. This function is convenient because you do not need to manually create an array of x values. MATLAB samples the function over the plotting interval.

    Example \(\PageIndex{1}\)

    Plotting a function

    syms x
anExpr = x^3 + 3*x^2 - 2;
fplot(anExpr, [-5 5])
grid on
xlabel('x')
ylabel('f(x)')
title('Symbolic Function Plot')
    Solution

    clipboard_ee7910abf3456a30e6f3f880ffa9a69b3.png

    If no interval is specified, fplot uses a default range. To choose a specific domain, provide a two-element vector.

    fplot(anExpr, [-5 5])

    11.2 Plotting a Function and Its Derivative

    A useful way to understand derivatives is to plot a function and its derivative on the same graph.

    Example \(\PageIndex{2}\)

    Plotting a function and its derivative

    syms x
f = x^3 - 4*x + 1;
df = diff(f);

fplot(f, [-3 3])
hold on
fplot(df, [-3 3])
grid on

xlabel('x')
legend('f(x)', 'df/dx')
title('Function and Derivative')
hold off
    Solution

    clipboard_e6cdcfac10808ec6f20cfe2c8303dc823.png


    This page titled 14.10: Plotting Symbolic Expressions was last modified on Tue, 30 Jun 2026 02:11:43 GMT and is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by Zara Noroozi.