Final answer:
The explicit formula for the geometric sequence is already given in exponential form as f(n) := 1,250(11)^(n-1), which serves directly as the exponential function for the sequence.
Step-by-step explanation:
The explicit formula given for a certain geometric sequence is f(n) := 1,250(11)n-1. The exponential function for this sequence has the same base form and simply reiterates the given formula. In a general sense, an exponential function would be represented as f(x)=abx, where a is the initial value, b is the base of the exponential growth, and x is the exponent representing the step or interval. In this specific case, the exponential function for the sequence keeps the base 11 and the coefficient 1,250, producing f(n) = 1,250 × 11n-1 when presented as an exponential function.