2. Hermann Ebbinghaus (1850-1909) pioneered the study of memory. A 2011 article in the journal of Mathematical Psychology presents the mathematical model R(t) = a + b(1 + at)\"3 for the Ebbinghaus forgetting curve, where R(t) is the fraction of memory retained t days after learning a task; a, b and c are experimentally determined constants between 0 and 1; is a positive constant; and R(0) 2 1. The constants depend on the type of task being learned. (a) What is the rate of change of retention t days after a task is learned? (b) Do you forget how to perform a task faster soon after learning it, or a long time after you have learned it? Why? Explain / justify your answers. (c) What fraction of memory is permanent? Explain / justify your