In general: For an exponential function whose exponent tends to +- oo as x->oo, the function tends to oo or 0 respectively as x->oo.
Note that this applies similarly for x->-oo Further, as the exponent approaches +-oo, minute changes in x will (typically) lead to drastic changes in the value of the function.
Note that behavior changes for functions where the base of the exponential function, i.e. the a in f(x) = a^x, is such that -1<=a<=1.
Those involving -1<=a<0 will behave oddly (as the f(x) will not take on any real values, save where x is an integer), while 0^x is always 0 and 1^x is always 1.
For those values 0<a<1, however, the behavior is the opposite of the long-term behavior noted above.
For functions a^x with 0<a<1, as x->oo, f(x) ->0, and as x->-oo, f(x) ->oo
