Write a user written function that expects as its input argument a vector of x values and a vector of corresponding y-values. The function must return a matrix with 3 columns. The first column must be the x-vector that was provided by the user. The other columns must contain approximations for the first derivative (dy/dx). Column 2 must contain forward difference approximations, column 3 must contain backward difference approximations. Populate the matrix with NaN if the method cannot be computed correctly for a given point.

Ihave a music player on my phone. i can buy songs, add them to playlists and play them. obviously it would be redundant to store each song in each playlist; each playlist is just a list of pointers to the songs. for this lab you will simulate this behavior. your program will need to have options to: add songs to the system library (you will store the text of the first line of the song, rather than the audio) add playlists add songs to a playlist list playlists play a playlist list all of the songs in the library with a count of how many times each song has been played remove a song from a playlist remove a playlist remove a song from the library (and thus from all playlists that contain it) note that we will not be checking many error cases. in real programming this would be bad, you should usually try to recognize and respond to as many types of errors as you can. in the context of class we are trying to acquaint you with as many concepts as possible, so for the sake of educational efficiency we will not be checking most errors in this lab, you may assume that your user provides correct input. you may add all appropriate error testing if you wish, but we will not be testing for it.

The total cost of textbooks for the term was collected from 36 students. create a histogram for this data. $140 $160 $160 $165 $180 $220 $235 $240 $250 $260 $280 $285 $285 $285 $290 $300 $300 $305 $310 $310 $315 $315 $320 $320 $330 $340 $345 $350 $355 $360 $360 $380 $395 $420 $460 $460

Apython programming question: assume s is a string of lower case characters. write a program that prints the number of times the string 'bob' occurs in s. for example, if s = 'azcbobobegghakl', then your program should print number of times bob occurs is: 2