I am currently doing a project in math regarding how to model the catenary section of the golden gate bridge, and I am trying to find the equation of...

I am currently doing a project in math regarding how to model the catenary section of the golden gate bridge, and I am trying to find the equation of the catenary in the form of y=1/a cosh(ax)+ c that passes through the following points (0,0), (640,227), (-640, 227). I was not able to do so for some reason. Can someone please help me find this specific equation ?

thanks