English: Comparison of a catenary (black dotted curve) and a parabola (red solid curve) with the same span and sag. The catenary represents the profile of a simple suspension bridge, or the cable of a suspended-deck suspension bridge on which its deck and hangers have negligible mass compared to its cable. The parabola represents the profile of the cable of a suspended-deck suspension bridge on which its cable and hangers have negligible mass compared to its deck. The profile of the cable of a real suspension bridge with the same span and sag will lie between the two curves. The catenary and parabola equations, plotted between x=-1 and x=1, are ${\displaystyle y={\text{cosh }}x}$ and ${\displaystyle y=x^{2}[({\text{cosh }}1)-1]+1}$, respectively.