Engineers and Scientists 1st Edition By Steven Chapra,
David Clough
When writing mathematical expressions involving vectors, it is often necessary to
include a period before multiplication (e.g. .*) when we desire element-by-element
multiplication because (select all that apply): - ANSWER -the default is matrix
multiplication as defined in linear algebra, not element-by-element multiplication.
-failure to do so may result in an error.
-failure to do so may yield unexpected numerical results
Many built-in functions will accept scalars or vectors as input arguments. In general
they operate element by element when the input is a vector.
T/F - ANSWER True
Below is a list of operations that may all be included in a single command. Please
put these in the order by which MATLAB evaluates them when executing the
command. Note operations on the same precedence level are executed left to right.
Also, the order of operations can be overridden using parentheses.
-exponentiation (^)
-multiplication and division (* /)
-addition and subtraction (+ -)
-parentheses () - ANSWER 1 - parentheses ()
2 - exponentiation (^)
3 - multiplication and division (* /)
4 - addition and subtraction (+ -)
Where you enter MATLAB commands at the prompt - ANSWER Command Window
Records all previous commands - ANSWER Command History
Tracks the values of variables as they are created and/or modified - ANSWER
Workspace
Indicates the folder on the computer where MATLAB is looking for files - ANSWER
Current Folder
The list below shows a variety of assignment commands. Select the ones that will
return errors or an incorrect/unexpected numerical answer if both x and y are vectors
of the same length:
1 - z = atand(y/x);
2 - z = 5*x.^2.*y+3*x.*y.^3
3 - z = 2*x.^2+1/y
4 - z = (x + y)/sqrt(x.^2+y.^2)
, 5 - z = 10*exp(-5*x).*cos(pi*y-pi/2)
6 - z = 10*cos(pi*x).*sin(pi*y).^2; - ANSWER 1,3,4
You are using MATLAB to find one of the sides of a right triangle. The hypotenuse is
7 and the known side is 4. Which of the following commands is correct? (More than
one option may be correct. Select all the correct options.)
1 - >>a = 4; c = 7; a^2 + b^2 = c^2
2 - >>a = 4; c = 7; b = sqrt(c^2 - a^2)
3 - >>a = 4; c = 7; b^2 = c^2 - a^2
4 - >>a = 4; c = 7; b = (c^2 - a^2)^0.5
5 - All of the above are correct - ANSWER 2,4
A script m-file is simply a list of MATLAB commands saved to a file. When the script
is run, these commands are executed sequentially using the same workspace as the
command window.
True/False - ANSWER True
Match the MATLAB command with the appropriate verbal explanation of what the
command is doing. All of these commands refer to a vector x = [2 -1 3 1.7 99 8]
z = x([2 5]).^2
z = x(1:4)
z = x(end-1:end);
z = x(4) - ANSWER z = x([2 5]).^2
- Square the second and
z = x(1:4)
-Assign the first through
z = x(end-1:end);
-Assign the last two elements
z = x(4)
-Assign the fourth element
Which of the following commands creates a column vector of the integers 1 through
5? Select all correct answers.
1 - x = linspace(1,5,5)';
2 - x = [1; 2; 3; 4; 5];
3 - x = [1:1:5];
4 - x = [1 2 3 4 5]';
5 - x = [1, 2, 3, 4, 5]; - ANSWER 1,2,4
Which of the following are NOT correct uses of MATLAB's built-in functions to do the
calculation indicated. Select all that are incorrect.