Chapter 2: Q38P (page 71)
The functions,are called 鈥渃ircular functions鈥 and the functions, are called 鈥渉yperbolic functions鈥. To see a reason for this, show that, satisfy the equation of a circle, while, satisfy the equation of a hyperbola
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Short Answer
It has been proved that the satisfies the equation of the circle and satisfies the equation of the hyperbola.