Each of Exercises 1–4 gives a value of sinh x or cosh x. Use the defi-nitions and the identity cosh2 x – sinh2 x = 1 to find the values of the remaining five hyperbolic functions.
1. sinh x = – 3/4
2. cosh x = 17 /15
3. sinh x = 4/3 .
4. cosh x = 13/ 5