as you know from calculus. The constant A represents the initial amount of the sample. We shall assume that the value of A is known exactly. The constant r is the decay rate. Suppose we have data from a sample and we wish to find r. You can check that if you know two data points exactly then r can be solved for exactly. However we shall add noise to the data. You are to adapt the least squares method to find the "best" value of r.