I learned about PCA and how to find the principal components via eigenvectors/values. Now for the following problems my professor says that "Feature 2 is constant and can hence be ignored, so you can produce a scatter plot of feature 1 versus 3, and then you can see the main axes:"
So I should be able to draw a scatter plot and then see the main axes (eigenvectors) of the data. I must severely misunderstand something because when I draw the scatter plot I don't see the connection between the solution and the plot.
How to see (no computation of eigenvectors/values) the principal components in such simple plots?