Why can a problem with extra information be difficult to solve?

Use the method of cylindrical shells to find the volume v generated by rotating the region bounded by the curves about the given axis. y = 7ex, y = 7e^-x, x = 1; about the y-axis

How do i find the missing angle measure in a polygon

Given a binomial distribution variable with n=20 and p=0.60 find the following possibilities using the binomial table a) p(x < 13) b) p x > 15) c) p(x = 17) d) p(11 < x < 14) e) p(11 < x < 14)