Neil_UK February 2016
x = np.linspace ... is creating an x array
I suspect that you want to create a y array, and then plot y against x.
Using numpy, there is no need to do the python loop thing for x_elem in x:, as numpy lets you work directly with arrays.
y = 2*20 / 500*x
will create a y array of the same length as x.
Then try the rest of your plot program.