A cable hangs between two poles of equal height and 30 feet apart. Set up a coordinate system where the poles are placed at x=-15 and x=15, where x is measured in feet. The height (in feet) of the cable at position x is
h(x)=14cosh(x/14)
where cosh(x)=(e^x+e^-x)/2 is the hyperbolic cosine, which is an important function in physics and engineering.