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matlabfunctionplotlimit

Matlab - how do I plot the limit when x reaches 0 in the function (x - sqrt(x)) / sqrt(sin(x))?

In Matlab - how do I plot the limit when x reaches 0 in the function (x - sqrt(x)) / sqrt(sin(x)) ?

I've just started programming, so I'm very new to this.

I've been trying to plot the function in various ways, one of which is:

y = @(x) (x - sqrt.(x))./ (sqrt.(sin.*x));

fplot(y,[0.1 0.9], 200)

Which gives the following error code: Argument to dynamic structure reference must evaluate to a valid field name.

I've also tried without the function handle, like this:

x = linspace(0.1, pi/2, 200);
y = (x - sqrt.(x))./ (sqrt.(sin.*x));
plot(x, y)

Which gives the same error code as the previous one. I've tried without the dots, tried with different intervals and I don't understand the error code.

Solution

  • The bounds/range of the plot can be changed by adjusting X_Min, X_Max, Y_Min and Y_Max as you'd like.

    Plotting Functions With Limits

    Method 1: Using Anonymous Functions

    y = @(x) (x - sqrt(x))./(sqrt(sin(x)));

X_Min = -5;
X_Max = 20;
Y_Min = -100;
Y_Max = 100;

fplot(y,[X_Min X_Max]);
axis([X_Min X_Max Y_Min Y_Max]);

    Method 2: Using Array Inputs/Vectors

    This method depends highly on the plotting interval/density. Unfortunately, this method does not show dotted lines on the limits unlike method 1.

    X_Min = -5;
X_Max = 20;
Y_Min = 0;
Y_Max = 100;

Plotting_Density = 1000;
x = linspace(X_Min, X_Max, Plotting_Density);
y = (x - sqrt(x))./(sqrt(sin(x)));

plot(x, y);
axis([X_Min X_Max Y_Min Y_Max]);

    Extension:

    The use of the . implies elemental operations. Using . will apply the function to all the elements of an array. In this case, it is not necessary to use the . operation since the term x is used in an anonymous function.

    • "./" -> Division over all elements in array

    • ".*" -> Multiplication over all elements in array

    Using MATLAB version: R2019b