error: Python exception: ShapeError: Matrix shapes must agree (5, 1) != (4, 1)

 syms x
 f(x)=4*x^2+20*x+4
 fplot(@(x) f, [-10 5])

This is what I've written in octave so far and I keep getting this error:

 error: Python exception: ShapeError: Matrix shapes must agree (5, 1) != (4, 1)
    occurred at line 3 of the Python code block:

    return x.multiply_elementwise(y.applyfunc(lambda a: 1/a)),
error: called from
    pycall_sympy__ at line 178 column 7
    rdivide at line 104 column 5
    interp1 at line 307 column 13
    fplot at line 201 column 8

Like, I freaking don't get it. What am I doing wrong? Thanks in advance!