Q1. Problem Solving in Engineering and Science is composed of 5 steps.
Complete the missing step below:
1. State the Problem
2. Describe the input and output
3. Describe the algorithm to solve
the problem
4. Solve the problem
5. ???
A1. The last step is to test or check out the results (the
output) to see if they make sense. For instance, you want to find what the
price per unit of a pizza pie is. The entire pizza is $9.99 and the resultant price
per unit you found after step 4 is $15. This result obviously does not make
sense! Price per unit can not be more than what the price of the entire pizza
is! You should go back and check out step
1 through 4.
Q2. Give one example for each of the
following:
scalar value, vector, column vector, a 2x3 matrix
A2.
scalar: any single dimensional value . E.g.: 45, 60.
vector: is a 1xn matrix, where 1 is the number of rows, n is the
number of columns. E.g.: [10
20 30]
column vector: is a nx1 matrix, where n is the number of rows, 1 is
the number of columns.
E.g.:
10
20
30
a 2x3 matrix: has 2 rows and 3 columns.
Eg:
10 20 30
40 50 60
Q3. What does each of the following
MATLAB commands do?
whos, save,
load
A3.
whos: shows the information (name, type, size, attributes but not the value!) of the variables available in the current workspace.
save: saves the variables in the current workspace in
to a file. The type of the file can be a .mat
or .dat file.
.mat file is a binary file, which is
only recognized by the MATLAB. .dat file is an ASCII file (a text file), which can
be opened or viewed by other programs or text editors.
To save variables in to a .mat file, you can use the MATLAB
command:
save temp.mat
This creates a temp.mat file with
all the variables currently available in the workspace.
load: loads the variables from a .mat or .dat file into the current workspace.
For instance,
load temp.mat
Loads all the variables in the temp.mat file into the current workspace.
As an exercise and to understand save and load commands of MATLAB, open a MATLAB session on Strauss.udel.edu in a
SunRay machine or using
SSH from a Windows PC or laptop, type the following commands in the MATLAB
command prompt, and observe what happens (Note that, A and B are the variables created in your current workspace).
|
clear clc A = [1 2 3] B = 66.7 whos A B save temp.mat clc whos A B load temp.mat whos A B |
Q4. What happens when we type the
following at the MATLAB command prompt?
>> B = [10, 20, 30; 40, 50, 60]
A4. A matrix B with 2 rows and 3 columns is created and echoed (printed)
on the MATLAB command prompt. That is,
|
>> B = [10, 20, 30; 40, 50, 60] B = 10 20
30 40 50
60 |
Q5. Give 2 examples of a Unix shell command
A5. ls, cd, mkdir, pwd (check out chapter 1 and 2 of
the Unix book to make yourself familiar with the some of the Unix shell commands
that you will frequently use in the future!)