Plotting Curves

Plotting XY Data

Syntax

plot(X,Y, 'options')

creates a 2-D line plot of the data in Y versus the corresponding values in X, where X and Y are vectors of the same length.

Plotting function

fplot(f,xinterval)

plots expression or function f over the specified interval. Specify the interval as a two-element vector of the form [xmin xmax].

If we did not mention xinterval, fplot plots the function f over the default interval [-5 5] for x

Example

Plot the functions   $$y1=50cos(x)sin(x),\\y2=4x^3-4x+14,\\y3=10x$$ in the range [-2,2]. 

Using plot

clc

clear

close

 

x = [-2:0.01:2];

%Define the functions to plot

y1 = 50*cos(x).*sin(x);

y2 = 4*x.^3-4*x+14;

y3 = 10*x;

 

plot(x,y1,'b','linewidth',1)

hold on

plot(x,y2,'--r','linewidth',1)

plot(x,y3,'-.m','linewidth',1.5)

hold off

%Customization (Optional)

xlabel('\bf x-Axis'); ylabel('\bf y-Axis')

title('\fontname{Arial} Cartesian Plot','fontsize',14)

 

legend('y1','y2','y3')

 

Output

 

Using plot

clc

clear

close

syms x

y1 = 50*cos(x)*sin(x);

y2 = 4*x^3-4*x+14;

y3 = 10*x

 

fplot([y1,y2,y3],[-2,2])

 

%Customization (Optional)

xlabel('\bf x-Axis'); ylabel('\bf y-Axis')

title('Cartesian Plot','fontsize',14)

legend('y1','y2','y3')

 Output

Plotting Polar plot

 Syntax

polarplot(theta,rho)

plots a line in polar coordinates, with theta indicating the angle in radians and rho indicating the radius value for each point. The inputs must be vectors of equal length or matrices of equal size.

Example

Plot the graph of the polar curves $$r=cos(2\theta); r=sin(3\theta)$$

clc

clear

close all

t=linspace(0,2*pi);

r1=input("Enter the first polar curve r1=f(t): r1=");

r2=input("Enter the second polar curve r2=f(t): r2=");

polarplot(t,r1,'m',t,r2,'b','linewidth',2);

 Output