Week 5 ENCMP 100

Question 1

What is a vector

Answer 1

A vector is a special case of a matrix in which one of the dimensions is 1

Question 2

What does the ‘char’ function do?

Answer 2

the function char converts an integer to the character equivalent

Question 3

What does size() do?

Answer 3

size returns the # of rows and columns for a vector or matrix

Rows x Columns

Question 4

What is the default data type in MATLAB?

Answer 4

The default data type is double

Question 5

What does ‘subplot’ do?

Answer 5

The subplot function creates a matrix (or vector) in a
Figure Window so that multiple plots can be viewed at
once

Question 6

What data types are supported in MATLAB

Answer 6

Real numbers, Integers, Characters and Strings, Logical & Complex Numbers

Question 7

Abs means what?

Answer 7

Absolute value

Question 8

Function ‘complex’ creates what?

Answer 8

A complex array

Question 9

Conj creates what

Answer 9

Complex conjungate

Question 10

What does ‘i’ do?

Answer 10

It is a imaginary unit

Question 11

What does ‘imag’ do?

Answer 11

It is the imaginary part of a complex number

Question 12

What does the colon operator do?

Answer 12

Colon operator: iterates through values in the form first:step:last
e.g. 5:3:14 returns vector [5 8 11 14]

Question 13

What does .* do?

Answer 13

It is an array multiplication operator

Question 14

How do you do array division?

Answer 14

array division: A ./ B, A .\ B

Question 15

How do you do array exponential

Answer 15

array exponentiation A .^ 2

Question 16

What is matrix multiplication

Answer 16

In MATLAB, the multiplication operator * performs matrix
multiplication

In order to be able to multiply a matrix A by a matrix B, the number of
columns of A must be the same as the number of rows of B

If the matrix A has dimensions m x n, that means that matrix B must
have dimensions n x something; we’ll call it p
- In mathematical notation, [A]m x n [B]n x p
-We say that the inner dimensions must be the same

Question 17

What is the difference between a matrix and array multi platoon

Answer 17

Confusing matrix multiplication and array multiplication. Array
operations, including multiplication, division, and exponentiation, are
performed term by term (so the arrays must have the same size); the
operators are .*, ./, .\, and .^. For matrix multiplication to be possible,
the inner dimensions must agree and the operator is *.

Question 18

What is ASCII

Answer 18

standard ASCII has 128 characters; integer equivalents are 0-127

Question 19

Is subplot row wise or columnwise

Answer 19

It is rowwise

Question 20

What is Linear Indexing

Answer 20

Linear indexing: only using one index into a
matrix (MATLAB will unwind it column-by
column)
 Note, this is not generally recommended

Question 21

What can be used to determine the number of elements in a vector

Answer 21

Instead, use the function length or numel to
determine the number of elements in a vector, and the function size
for a matrix:
len = length(vec); [r, c] = size(mat);

Question 22

What does the plot function do?

Answer 22

77

Question 23

The ASCII codes for the letters a and d are 97 and 100, respectively. What are the values of v1 and s1, respectively?
v1 = ‘a’+3;
s1 = [‘a’ 100];

Answer 23

100 & ad

Question 24

What is a sinusoid function?

Answer 24

https://dademuch.com/2020/10/07/the-sinusoidal-characteristics-in-discrete-time-matlab/

Question 25

What is the dimensional limit for array operations?

Answer 25

this means the matrices must have the same dimensions

Question 26

Assume the following array:
c=[1 2;5 6;9 10];
What is the contents of the following array: d = c(:,3)?

Answer 26

Not possible because the column number is outside possible options for the matrix

Question 27

my_area = 12;
str = [‘The area is’ num2str(my_area)];
disp(str);

Answer 27

The area is12

Question 28

Variable names must begin with what?

Answer 28

Letters of the alphabet

Question 29

How do I have the program check what the limit is for the length of the variable name

Answer 29

the built-in function namelengthmax tells what the

limit is for the length of a variable name

Question 30

arr1 = [0 2 1 0; 3 4 0 5; 10 2 1 7];
s = size(arr1)

Answer 30

[3,4]