Homework Sourselim x goes to infinity e3x e3xe3x e3xWhat rule do I use an
lim x goes to infinity (e^3x - e^-3x)/(e^3x + e^-3x)....What rule do I use?? and why do I need to divide top and bottom by e^3x...What is the reason?...What should I be looking for??
Solution
you need to divide num and denom by e^3x so that you are left with the terms none of which will go to infinity if x goes to infinity hence we can substitute x=infinity in this case after dividing by e^3x we have (1-e^-6x)/(1+e^-6x) now e^-6x goes to 0 as x goes to infinity hence lim as x goes to infinity((1-e^-6x)/(1+e^-6x))=1
