Question: (a) Using a calculator or computer, sketch the graph of y = 2ex + 5e-x for -3 ≤ x ≤ 3, 0 ≤ y ≤ 20. Observe that it looks like the graph of y = cosh x. Approximately where is its minimum?
(b) Show algebraically that y = 2ex + 5e-x can be written in the form y = A cosh(x - c). Calculate the values of A and c. Explain what this tells you about the graph in part (a).