MECH 322: Lab Assignment 4¶

Getting Started with Octave and the Jupyter Notebook (100 points)¶

NAME: Sample

Enter the following command into the cell below this text and press Shift and Enter on your keyboard at the same time to execute it.

ctime(time)

You have issued your first Octave command. Congratulations!

ctime(time)

ans = Tue Jan 24 01:35:19 2017

Your answer above should be similar to the following:

ans = Thu Nov 26 22:38:23 2016

Purpose¶

Start using Octave (a free, open-source alternative to MATLAB™) for performing basic math operations. Assignments will be presented through SageMathCloud via open-source Jupyter notebooks, the built-in text editor, and the built-in terminal command line.

Initial Tasks¶

Click on the Files icon above the Jupyter logo
Check the box to the left of the name of this file Lab 04 Octave Intro.ipynb then click on the "Duplicate" button
Change the name to add - FerrisID (your Ferris ID) before the file extension i.e. Lab 04 Octave Intro - bradyb.ipynb (Files that are not renamed will not be graded)
Edit the new file for submitting and grading. Click on the new file to open it and start the editing process.
Double-click in the Markdown cell that says NAME: located below the title and subtitle cells at the top of the page and enter your name after the last ** pair. Press Shift and Enter (Shift-Enter) on your keyboard at the same time to execute the cell.
Enter the timecode command shown below your name into the input cell provided and use Shift-Enter to execute it
Follow along in class as we use Octave to perform basic mathematical operations and functions
Finish the assignment by following the instructions at the end of this document.

Basic Arithmetic¶

Using the basic math operators (+, -, *, /, ^) write each of the following in standard math format (like you would on a piece of paper in math class) in the space provided next to the Octave commands on the handout.

Repeat (type) each of the commands in the blank code cells below the commands and press Shift-Enter to execute each command.

7 + 8/2

7 + 8/2

ans =  11

(7 + 8)/2

(7 + 8)/2

ans =  7.5000

4 + 5/3 + 2

4 + 5/3 + 2

ans =  7.6667

5^3/2

5^3/2

ans =  62.500

5^(3/2)

5^(3/2)

ans =  11.180

27^(1/3) + 32^0.2

27^(1/3) + 32^0.2

ans =  5

27^1/3 + 32^0.2

27^1/3 + 32^0.2

ans =  11

Formatting Output¶

Create the comment % Formatting output in the following cell. You can use % or # at the beginning of any code line to create a comment.

% Formatting output

You can also add a comment anywhere in the Jupyter Notebook by inserting a Markdown cell, typing away, and then using Shift-Enter to execute the cell.

Insert a cell below this one by clicking on this cell and then clicking on the + button in the tool bar or by using the keyboard shortut b. Change the cell type to Markdown using the pop-up list in the tool bar or by using the keyboard shortcut m. Click in the new cell and type anything you want. Use Shift-Enter to execute the cell.

Check out the display formatting command, format, by using Octave to determine the answer to 1/999 for each of the following format settings. You will need to change the format then perform the math for each format change. This can be easily accomplished by issuing two commands on the same line separated by a comma, such as:

format long, 1/999

After entering the each of the 9 formatting commands in the 9 code cells below use Shift-Enter to execute and see the results of each.

format short, 1/999

format short, 1/999

ans =  0.0010010

format long, 1/999

format long, 1/999

ans =  0.00100100100100100

format short e, 1/999

format short e, 1/999

ans =    1.0010e-03

format long e, 1/999

format long e, 1/999

ans =    1.00100100100100e-03

format short g, 1/999

format long g, 1/999

ans =    0.001001001001001

format long g, 1/999

format long g, 1/999

ans =    0.001001001001001

format bank, 1/999

format bank, 1/999

ans =  0.00

format compact and format loose are used to change the spacing around results in the Octave stand-alone application, but have no affect in the Jupyter Notebook

Set the format back to short using the command format short in the following cell (don't forget to execute the command).

format short

Elementary Math Functions¶

Try out each of the built-in math functions shown in Table 1-3 of the textbook using values of your choice (not x). Write your expression in standard math notation on the handout next to each Octave function using your values.

sqrt(x)
nthroot(x,n)
exp(x)
abs(x)
log(x)
log10(x)
factorial(x)

Jupyter allows multiple commands to be executed in the same cell or each in its own cell. Type each of these commands in its own cell, making sure you execute each cell after by pressing Shift-Enter.

sqrt(5)

ans =  2.2361

nthroot(125,3)

ans =  5

exp(2)
e^2

ans =  7.3891
ans =  7.3891

abs(-10)

ans =  10

log(100)

ans =  4.6052

log10(100)

ans =  2

factorial(6)

ans =  720

Trigonometric Functions¶

Try out some of the built-in trigonometric functions shown in Table 1-4 of the textbook using the given values. Type each group of commands into the cells provided then execute them.

Sine and Inverse Sine¶

sin(pi/4)
sind(30)
asin(0.6)
asind(0.6)

sin(pi/4)
sind(30)
asin(0.6)
asind(0.6)

ans =  0.70711
ans =  0.50000
ans =  0.64350
ans =  36.870

Cosine and Inverse Cosine¶

cos(pi/4)
cosd(60)
acos(-0.4)
acosd(-0.4)

cos(pi/4)
cosd(60)
acos(-0.4)
acosd(-0.4)

ans =  0.70711
ans =  0.50000
ans =  1.9823
ans =  113.58

Tangent and Inverse Tangent¶

tan(2*pi/3)
tand(115)
atan(1.2)
atand(0.8)

tan(2*pi/3)
tand(115)
atan(1.2)
atand(0.8)

ans = -1.7321
ans = -2.1445
ans =  0.87606
ans =  38.660
__stdin_prompt>

Rounding functions¶

Determine the answer to each of the following rounding commands from Table 1-5 in the textbook by hand and write the answers in the spaces provided on the handout, then try out each of the functions using Octave in the following cells (one command per code cell).

round(1.6)
fix(1.6)
ceil(1.6)
ceil(-33.3)

floor(1.6)
floor(-44.99)
rem(7,5)
mod(7,5)
sign(-0.1)

Assigning Variables¶

Issue each of the following commands related to assigning and using variables. Keep in mind that Octave is case-sensitive, meaning that a and A are not the same. Variable names must start with a letter and can also contain numbers and underscores, but spaces are not allowed.

a=12
B=4
C=(a-B)+40-a/B*10
ABB=72;
abb=9;
ABB/abb
x=0.75;
E=sin(x)^2 + cos(x)^2

Miscelaneous commands¶

Issue each of the following miscellaneous commands in there own code cells. Be sure to execute each cell.

pi
e
inf
i
j
who
whos

2*3;
ans
clear a;
who
clear;
who
clc

Congratulations!!! You have finished the first Octave assignment.¶

Assign your name to a variable called "name" in the cell below this one and execute the cell. Your name must be placed between single quotes like the following example. Make sure to use your name, not mine.

name = 'brian brady'

In the following cell enter the command to show below; the time and date you finished the assignment.

ctime(time)

Click on the Save icon and then click on the $\times$ next to the notebook name in the blue tab. This assignment must be completed before the end the lab session in order to receive credit. The instructor will automatically collect your file at that time and no further edits will be graded.