Hi, I'm new to programming in excel and I have an assignment in class where I have to write an excel function that calculates a hyperbolic secant and the formula is cosh(u)=(e^u+e^-u)/2 and another formula to use is hyperbolic secant=1/cosh(u).

If someone can help me start it or types down couple of the first lines of program and explain what I should after, that would be great.
thank you

And also when I program, do I need to type something on one of the worksheets, if so, what do I type.