Photo by: Alila. Exocytosis is the cellular process in which intracellular vesicles in the cytoplasm fuse with the plasma membrane and release or secrete their contents into the extracellular space.
More generally, the formula for the 95% confidence interval on the mean is: Lower limit = M - (tCL)(sM) Upper limit = M + (tCL)(sM) where M is the sample mean, tCL is the t for the confidence level desired (0.95 in the above example), and sM is the estimated standard error of the mean.
In order for a function to have a limit at x =a, in your case a =0, then the limit when x approaches a from the right must equal the limit when x approaches a from the left. In this case, the limit from the left is -1 and the limit from the right is 1. So, the only candidates to limit of f at 0 are -1 and 1.