'XNH8QLYHUVLW\ (GPXQG73UDWW-U6FKRRORI(QJLQHHULQJ. EGR 103L Fall Skills Quiz. Rebecca A. Simmons and & Michael R.

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1 'XNH8QLYHUVLW\ (GPXQG73UDWW-U6FKRRORI(QJLQHHULQJ EGR 103L Fall 2014 Skills Quiz Rebecca A. Simmons and & Michael R. Gustafson II NET ID (please print): In keeping with the Community Standard, I have neither provided nor received any assistance on this test. I understand if it is later determined that I gave or received assistance, I will be brought before the Undergraduate Conduct Board and, if found responsible for academic dishonesty or academic contempt, fail the class. I also understand that I am not allowed to speak to anyone except the instructor about any aspect of this test until the instructor announces it is allowed. I understand if it is later determined that I did speak to another person about the test before the instructor said it was allowed, I will be brought before the Undergraduate Conduct Board and, if found responsible for academic dishonesty or academic contempt, fail the class. Signature: Notes You will be turning in each problem in a separate pile. Most of these problems will require working on additional pieces of paper - Make sure that you do not put work for more than any one problem on any one piece of paper. For this test, you will be turning in four different sets of work. Again, Please do not work on multiple problems on the same sheet of paper. Also - please do not put work for one problem on the back of another problem. Be sure your name and NET ID show up on every page of the test. If you are including work on extra sheets of paper, put your name and NET ID on each and be sure to staple them to the appropriate problem. Problems without names will incur at least a 25% penalty for the problem. This first page should have your name, NET ID, and signature on it. It should be stapled on top of and turned in with your submission for Problem I. You will not need and can not use a calculator on this test. You will be asked to write several lines of code on this test. Make sure what you write is MATLAB code and not mathematics. Be very careful with any symbols you use. You do not need to put the honor code statement in your codes. The honor code statement on this page and your NET ID on each problem stands in for that.

2 Problem I: [25 pts.] Run It, Show It For each of the following sections, show what the matrices created or modified in each block will look like once you run each snippet of code. (1) >> A = (1.3):(-0.7):(-2.0) >> B = fix(a) >> C = ceil(a) >> D = floor(a) >> E = round(a) (2) >> F = 6:3:17 >> G = linspace(-3, 0, 7) >> H = logspace(2, 5, 4) (3) >> I = [6-4 3; ] >> J = size(i) >> K = size(i, 2) >> L = length(i) >> M = numel(i) >> N = I([2 1], [3 1]) (4) >> Oh = [ ] >> P = Oh<=6 >> Q = Oh==2 >> R = 4<Oh & Oh<=6 >> S = Oh(find(Oh<5)) >> T = Oh.*(Oh>7)

3 Problem II: [25 pts.] Loop It, Write It (1) Write the output of the following MATLAB code: clear A = [ ]; B = [ ]; K=1; while K<5 fprintf( ³%0.0f: (%6.2f,%3.2f)\n ³, K, A(K), B(K)) K = K + 1; end fprintf( ³K is now: %8.3f\n ³, K) Note that the only space in the first argument of the first fprintf command is after the colon there is no space after the comma. There are spaces after the K, s, and colon in the second fprintf command. Put a single character in each of the boxes below and use the exact spacing MATLAB would produce: (2) Write what the matrix A, the matrix B, and the matrix C will be at the end of this code: A = 1; for B=2:4 A(1,B) = A(1,B-1) + 2*B; C(B,5-B)= B; end (3) Write an anonymous function LOC(a, b, g) that will calculate: for inputs a, b, and g that are appropriately sized matrices. LOC(a, b, g) = a 2 + b 2 2ab cos(g)

4 Problem III: [25 pts.] Load It, Plot It (1) You are given a data file called YourVals.dat and told that the first column contains a time, in seconds, at which a temperature and a pressure reading were taken. The temperature, in Kelvin, is contained in the second column and the pressure, in pounds per square inch (psi), is in the third column. You do not know in advance how many readings there are - only that they start at time 0 sec and are taken every 10 seconds over the course of the experiment. Write code that does the following: (a) Loads the data set and stores it in a matrix called ExpData. (b) Creates matrices called Times, Temps, and Pressures that contain the appropriate information from the ExpData matrix. (c) Determines the average pressure throughout the experiment and displays it using the %0.2e printing code for example Average pressure: 1.46e+01 psi (d) Determines the value of the maximum temperature and displays the time and pressure at which it happens using the %0.2e printing code for example: Max temp: 3.94e+02 K at 1.30e+02 sec and 1.48e+01 psi (e) Makes a graph of the temperature as a function of the time in minutes using data from the readings that are whole numbers of minutes - that is, the entries for every sixty seconds starting with 0. The graph should use a solid black line in this case, you do not need to include labels, a title, or a grid. You do not need to save the graph. (2) Write all the code necessary to replicate the plot below. The programmer used 1000 data points between 0 and π 2 to make the graph. The extents of the graph (the limits) were chosen by MATLAB. MATLAB also chose the best possible location for the legend. Also include code to put the plot in a file called DaftPlot.eps. The legend explains what exactly is being plotted. 1 Current vs. Time for a Circuit (NETID) i(t), A 0.5 e 2t cos(8t) e t sin(4t) t, sec

5 Problem IV: [25 pts.] Check and Mask It For this problem, you are going to be writing a function called OnePulse. The OnePulse function is defined as follows: {( ) + c a <= t <= b that will have four inputs: OnePulse(t, a, b, c) = 1 b a A vector, locally called t, that contains a single row or column of values, c otherwise Two single numbers, locally called a and b, that define how OnePulse works, and A single number, locally called c that is used in calculating the value of OnePulse. Your function must be written in such a way that it will check to make sure there are at least three inputs. Should the fourth input not be given, the program should run assuming that c=0 and print out a line that tells the user that. Should there be fewer than three inputs, the program should give an error that says Not enough inputs! After checking for the right number of inputs, you also need to make sure the inputs are appropriate. Your function should therefore check for the following: t needs to be a single row or column, otherwise the program should report an error that t is wrong shape! Both a and b need to be single values; in cases where either has more than one entry, the program should report an error of bad pulse limits! b needs to be larger than a; otherwise, your program should report an error of reversed pulse! In cases where the user calls the functions with valid inputs, the program should calculate the OnePulse value for the entries in t. You are not allowed to use any loops for this problem. The following shows several test cases for this function note: MATLAB takes care of printing the part): >> OnePulse([1 2 3], 4) Not enough inputs! >> OnePulse([1 2; 3 4], 5, 6, 7) t is wrong shape! >> OnePulse(1, [2 3], 4, 5) bad pulse limits! >> OnePulse(1, 2, [3 4], 5) bad pulse limits! >> OnePulse([ ], 3.5, 1.5) Assuming c=0 reversed pulse! >> OnePulse([ ], 1.5, 3.5) Assuming c=0 ans = >> OnePulse([ ], 3.5, 1.5, 2) reversed pulse! >> OnePulse([ ], 1.5, 3.5, 2) ans =