MATLAB onramp

Question 1

State which key symbolises multiplication

Answer 1

*

Question 2

State which key symbolises division

Answer 2

/

Question 3

State what a semicolon means

Answer 3

A semi colon suppresses the output

Question 4

State what pressing the up arrow does

Answer 4

Pressing the up arrow recalls previous commands

Question 5

Describe how to name a matlab variable

Answer 5

A matlab variable must start with a letter and contain only letters, numbers and underscores

Question 6

State how to clear all workspace variables

Answer 6

Type in the command “clear”

Question 7

State how to clear the command window

Answer 7

Type in the command “clc”

Question 8

State the matlab constant for π

Answer 8

pi

Question 9

State the matlab function for absolute values

Answer 9

abs

Question 10

State the matlab function for calculating eigenvalues

Answer 10

eig

Question 11

State the matlab function for calculating square roots

Answer 11

sqrt

Question 12

Describe an array

Answer 12

All matlab variables are called arrays - each variable can be more than one number.

Question 13

Describe a scalar

Answer 13

A scalar is one number, ie a 1 by 1 array (1 row by 1 column)

Question 14

Describe how to create arrays with multiple elements

Answer 14

Using square brackets, you can create arrays. Eg x = [3 5]

Question 15

Describe how to create an array with elements in a single row (a row vector)

Answer 15

Separate the elements using a space or a comma

Question 16

Describe how to create an array with elements in a single column (a column vector)

Answer 16

Separate the elements using a semicolon.

Question 17

Describe how to create a matrix

Answer 17

Enter the matrix row by row, separating the rows by semicolons

Question 18

Describe a short method of writing a row vector containing consecutive increasing integers

Answer 18

enter first:last (note you do not need square brackets)

Question 19

Describe a short method of writing a row vector containing integers of a particular spacing

Answer 19

enter first:spacing:last

Question 20

Describe how to enter a row vector of unknown spacing if you know the first and last numbers and the total number of columns

Answer 20

Using the linspace fucntion: linspace(first,last,number_of_elements) (note the use of commas)

Question 21

Describe how to transpose a row vector to a column vector

Answer 21

( ‘ ) is the transpose operator. You can either transpose x or transpose the parenthesis of a row vector

Question 22

Describe how to create a matrix of random numbers

Answer 22

Entering rand(a) where a will produce an a x a matrix of random numbers. Entering rand(a , b) will produce an a x b matrix of random numbers

Question 23

Describe how to create a zero matrix

Answer 23

Entering zeros(a) where a will produce an a x a matrix of zeroes. Entering rand(a , b) will produce an a x b matrix of zeroes

Question 24

Describe how to save a variable x to a given name

Answer 24

Enter “save foo x” to save variable x to a file called foo.mat

Question 25

Describe how to load a saved variable of a given name

Answer 25

Enter “load foo” to load a file called foo.mat

Question 26

Describe how to display the contents of of any variable

Answer 26

Enter the variable name

Question 27

Describe how to extract values from an array

Answer 27

Using row,column indexing. Eg y = A(6,7) will give you the element in the 6th row and 7th column of matrix A and label it y

Question 28

Describe the use of ‘end’

Answer 28

‘end’ refers to the end value in a row or column. You can also use end-1 to refer to the second to last value, etc

Question 29

Describe the colon operator ( : ) when used as an index

Answer 29

( : ) specifies all the elements in that dimension. Eg x = A(2,:) creates a row vector with all the elements from the second row of A. x=A(1:3,:) creates a matrix containing the first, second and third rows of matrix A

Question 30

Describe a single index value

Answer 30

A single index value can be used to reference a single element. Eg x=v(3) refers the the 3rd element of v when v is either a row or a column vector

Question 31

Describe a single range of index values

Answer 31

UP TO 5.2