This paper deals with two methods for determining the deflection line of a beam when bending. The determination of the deflection line under the influence of the action of different loadings for different modes of supporting the beam is observed. The deflection of the beam is a deformed longitudinal axis of the beam, and the displacement of the center of gravity in the perpendicular direction to the undeformed axis is the deflection of the beam. The angle by which the section is rotated relative to the original axis is called the angle of rotation. The differential equation of the deflection line is determined from the known mathematical formula for curvature. By the analytical method, the deflection and the angle of rotation are determined by consecutively integrating the differential equation of the deflection line. The graphoanalytic method is based on the analogy between the differential equation of the deflection line of the beam and the differential equation that relates the bending moment and the intensity of the load. A fictitious load, having the form of a bending moment diagram constructed on a real beam, is applied to a conjugate beam, of the same length and stiffness as the actual one.