Assignment:
(i) Prove that
cosh 2θ = sinh2 θ + 1
(ii) A chain hangs in a shape called a catenary, the equation of which is
f(x) = a cosh (x / a)
Determine the value of x when f(x) = 48 and a = 35.
Provide complete and step by step solution for the question and show calculations and use formulas.