explain h1.marker='o'; in matlab

h1 most likely refers to a handle to a plot, and marker='o' sets the type of marker used to display the data points on the plot to a circle.

Here's an example of a plot with markers in MATLAB:

main.m
% create some example data
x = linspace(0,2*pi,20);
y = sin(x);

% plot the data, setting the marker type to a red circle
h1 = plot(x, y, 'ro');

% add labels and titles to the plot
xlabel('x');
ylabel('sin(x)');
title('Plot with Circle Markers');
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This code produces a plot of the sine function with red circles at each data point.