English: The resonant curves for the fundamental harmonic of the nonlinear oscillator with damping are presented. The growth of the number of the curve corresponds to the growth of the amplitude of the driving force. The third curve is a grid curve for a system of curves with a unique dependence between the frequency of the driving force and the deviation of the system from the equilibrium position. For larger amplitudes, there is a fundamentally important feature for nonlinear systems-the dependence between the frequency of the driving force and the response of the system becomes ambiguous. The curves are constructed in the normalized coordinates: \ Delta = (\ gamma ^ 2-1) Q and y = 3/4 \ epsilon Q \ xi_1 ^ 2. Here Q is the quality of the oscillator and \gamma is the ratio of driving force frequency and eigenfrequency corresponding linear system without damping.