Generate a vector of exactly 25 colors from the built-in palette terrain.colors and name it tcols. Then, using a reversed version of it obtained via tcols[25:1], append the two vectors together to form a new vector of length 50 containing the first 25 colors shading one way and then the same 25 shading the opposite way.

Next, create and store an evenly spaced sequence of exactly 51 values between 3 and 3 inclusive; name it vals. Use dnorm to calculate and store the corresponding 51 values of the standard normal density curve; name it normvals.