An electric field is established in a nonuniform rod. A voltmeter is used to measure the potential difference between the left end of the rod and a point a distance x from the left end. The process is repeated, and it is found that the data are described by the relationship ΔV = Ax2, where A = 820 V/m2. What is the x-component of the electric field at a point 33 cm from the left end?