The shaft shown in Figure P11-4 was designed in Problem 10-19. For the data in row (a) of Table P11-1, and the corresponding diameter of shaft found in Problem 10-19,….

## Generate a pseudo-random sequence of 256 data points in a vector x, using the randn function which is built in to MATLAB.

Using MATLAB,

(a) Generate a pseudo-random sequence of 256 data points in a vector x, using the randn function which is built in to MATLAB. (b) Find the DFT of that sequence of data and put it in a vector X. (c) Set a vector Xlpf equal to X. (d) Change all the values in Xlpf to zero except the first 8 points and the last 8 points. (e) Take the real part of the inverse DFT of Xlpf and put it in a vector xlpf. (f) Generate a set of 256 sample times t which begin with 0 and are uniformly separated by 1. (g) Graph x and xlpf versus t on the same scale and compare. What kind of effect does this operation have on a set of data? Why is the output array called xlpf?