Math Help - Catenary Curve in Matlab...Help!!

1. Catenary Curve in Matlab...Help!!

A catenary is the curve formed by a hanging cable. Assume that the lowest point is (0,0); then the formula for the catenary is y = C cosh(x/C) - C .
To determine the catenary that goes through (a,b) or (-a,b) we must solve the equation b = C cosh(a/C) - C for C .

a) Show that the catenary through (10,6) or (-10,6) is y = 9.1889cosh(x/9.1889) - 9.1889

Someone plz help me on this one....I would really appreciate that...Thanks