matplotlib x axis range goes over the set range

[Pedroski55]

I am just trying to do some simple plots, nothing fancy.

So I am trying y = x**2

I thought I set x in the range -4 to +4 with: x = np.arange(-4, 4, 0.2), but I get range 0 to 40 for x. (I suppose there are 40 0.2s in 8)

I would like the zero on the x-axis to coincide with the zero on the y-axis.

2 small problems:

1. How do I set x-axis zero and y-axis zero in the same place?
Ideally, x and y zero should be in the centre of the figure, so I see -4 to +4 on both axes.
2. How can I fix the range of x? (I would like a small interval in the range in order to give a smooth curve.)

def tp():
    fig = plt.figure(figsize=(6, 6))
    x = np.arange(-4, 4, 0.2)
    y = x**2    
    ax = fig.add_subplot(121)
    #ax2 = fig.add_subplot(122)
    #ax.fig(num='This is the title')

    # Move left y-axis and bottom x-axis to centre, passing through (0,0)
    ax.spines['left'].set_position('center')
    ax.spines['bottom'].set_position('zero')
    # Eliminate upper and right axes
    ax.spines['right'].set_color('none')
    ax.spines['top'].set_color('none')

    # Show ticks in the left and lower axes only
    ax.xaxis.set_ticks_position('bottom')
    ax.yaxis.set_ticks_position('left')

    ax.set_title('Full view')
    ax.plot(y, color='blue', label='y = x^2')
    
    plt.xlabel("X axis")
    plt.ylabel("Y = x^2")
    plt.legend()
    plt.show()