The equation y = e^-4 can be evaluated using a graphing calculator by plugging in -4 for x and finding the corresponding y-value.
On a graphing calculator, this is usually done by setting the calculator to the "y=" mode and entering the equation y = e^x. Then, by entering -4 as the value of x, the corresponding y-value can be found.
The result would be y = e^-4 = 0.0183. To four decimal places, this value is 0.0183.