Answer:
e^x = 1 + x + x^2/2! + x^3/3! + x^4/4! + ...
where x is the power and
"!" means factorial such that n! means n*(n-1)*(n-2).......3.2.1
For e^-x, just replace x by -x,
e^-x = 1 - x + x^2/2! - x^3/3! + x^4/4! + ...
where x is the power and
"!" means factorial such that n! means n*(n-1)*(n-2).......3.2.1
eg: 4! = 4*3*2*1 =24
I hope this solves. You need to remember the expansion though.
