Plotting Cosine Waves Using Python Matplotlib And Numpy

Overview:

  • Cosine waves are periodic waves generated out of oscillations.

 

  • Cosine waves are similar to sine wave however the cosine wave leads sine wave by 90 degrees of phase angle.

 

  • The cosine curve does not go through the origin.

 

  • The cosine wave has the same frequency as its corresponding sine wave.

 

  • The ocean tides are an example of cosine waves.

 

  • A cosine curve can be plotted by calling the cosine() on a numpy array and using the plot() function of the pyplot module of matplotlib.

 

Example:

import numpy as np

import matplotlib.pyplot as plot

 

# Get x values of the cosine wave

time        = np.arange(0, 20, 0.2);

 

# Amplitude of the cosine wave is cosine of a variable like time

amplitude   = np.cos(time)

 

# Plot a cosine wave using time and amplitude obtained for the cosine wave

plot.plot(time, amplitude)

 

# Give a title for the cosine wave plot

plot.title('Cosine wave')

 

# Give x axis label for the cosine wave plot

plot.xlabel('Time')

 

# Give y axis label for the cosine wave plot

plot.ylabel('Amplitude = cosine(time)')

 

# Draw the grid for the graph

plot.grid(True, which='both')

 

plot.axhline(y=0, color='b')

 

# Display the cosine wave plot

plot.show()

 

Output:

cosine wave


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