Exponential Decay: the b value (growth factor) has been replaced either by (1 + r) or by (1 – r). The growth “rate” (r) is determined as b = 1 + r. The decay “rate” (r) is determined as b = 1 – r. a = initial value (the amount before measuring growth or decay)Click to see full answer. Thereof, what is the difference between growth rate and growth factor in an exponential function?Growth factor is the factor by which a quantity multiplies itself over time. Growth rate is the addend by which a quantity increases (or decreases) over time.Beside above, what does a represent in an exponential function? be an. exponential function where “b” is its change factor (or a constant), the exponent. “x” is the independent variable (or input of the function), the coefficient “a” is. called the initial value of the function (or the y-intercept), and “f(x)” represent the dependent variable (or output of the function). Accordingly, what is the growth or decay factor? A function of the form A(t) = Cat where a > 0 and a 1 is an exponential function. The number C gives the initial value of the function (when t = 0) and the number a is the growth (or decay) factor. If a > 1, the function represents growth; If 0 < a < 1, the function represents decay.What is the exponential formula?Remember that our original exponential formula was y = abx. You will notice that in these new growth and decay functions, the b value (growth factor) has been replaced either by (1 + r) or by (1 - r). The growth "rate" (r) is determined as b = 1 + r.