Matlab

Question 1

• MATLAB variable and file name conventions

Answer 1

cant start with a number
cant be the name of a fucntion
cant exceed namelengthmax
or be a keyword

Question 2

when to use ()

Answer 2

Use parentheses to specify precedence of operations, enclose function input arguments, and index into an array.

also indexing

Question 3

when to use []

Answer 3

Array construction

Array concatenation

Empty matrix and array element deletion

Multiple output argument assignment

Question 4

when to use {}

Answer 4

Cell array assignment and contents

Question 5

Difference between script & function

Answer 5

scripts can be run on their own but functions need to be called

Question 6

input

Answer 6

x = input(prompt)

Question 7

output

Answer 7

fprintf(‘Happy Birthday\n’);
fprintf(‘My name is %s\n’, prof_name);

disp(X)

Question 8

syntax

Answer 8

missing semicolon etc

Question 9

global workspace

Answer 9

avalable to everything

Question 10

local workspace

Answer 10

only avalable to the function that it is called in

Question 11

• What is considered “good practice”?

Answer 11

formatting and commenting

Question 12

2d plots

Answer 12

plot(X,Y)

Question 13

indexing arrays

Answer 13

do it 2d like

matrix(Row,Collum)

Question 14

matrix with integer referencing

Answer 14

matrix(num) num is the number of the array

Question 15

Array resizing and reshaping

Answer 15

ASK

Question 16

loading files matlab

Answer 16

load(filename)

Question 17

Element-wise operators

Answer 17

.* .^ ./

Question 18

Transposing arrays

Answer 18

array’

Question 19

Clc

Answer 19

Clear command window

Question 20

Close

Answer 20

Clear system memory

Question 21

find

Answer 21

k = find(X) returns a vector containing the linear indices of each nonzero element in array X.

Question 22

ans

Answer 22

funcitons as the most recent answer

Question 23

• Iskeyword

Answer 23

Tests if iskeyword(word) is a

Question 24

• zeros

Answer 24

creates an array of zeroes (row,collum)

Question 25

ones

Answer 25

creates an array of ones (row,collum)

Question 26

rand

Answer 26

uniformly distributed random numbers

Question 27

randn

Answer 27

Normally distributed random numbers

Question 28

randi

Answer 28

Uniformly distributed pseudorandom integers

X = randi(imax) returns a pseudorandom scalar integer between 1 and imax.

Question 29

linspace

Answer 29

y = linspace(x1,x2) returns a row vector of 100 evenly spaced points between x1 and x2.

Question 30

logspace

Answer 30

y = logspace(a,b,n) generates n points between decades 10^a and 10^b.

Question 31

length

Answer 31

n = length(X) returns the size of the longest dimension of X. If X is a vector, this is the same as its length.

Question 32

size

Answer 32

d = size(X) returns the sizes of each dimension of array X in a vector d with ndims(X) elements.

Question 33

numel

Answer 33

n = numel(A) returns the the number of elements, n, in array A.

Question 34

sort

Answer 34

B = sort(A) sorts the elements of A in ascending order.

If A is a vector, then sort(A) sorts the vector elements.

If A is a matrix, then sort(A) treats the columns of A as vectors and sorts each column.

Question 35

’

Answer 35

transposes teh array

Question 36

end

Answer 36

terminates the block of code

Question 37

round

Answer 37

= round(X) rounds each element of X to the nearest integer. In the case of a tie,

Question 38

xor

Answer 38

C = xor(A,B) performs a logical exclusive-OR of arrays A and B and returns an array containing elements set to either logical 1 (true) or logical 0 (false)

Question 39

max

Answer 39

M = max(A) returns the maximum elements of an array.

Question 40

mean

Answer 40

M = mean(A) returns the mean of the elements of A

Question 41

median

Answer 41

M = median(A) returns the median value of A.

Question 42

std

Answer 42

S = std(A) returns the standard deviation of the elements of A along the first array

Question 43

sum

Answer 43

S = sum(A) returns the sum of the elements of A along the first array dimension whose size does not equal 1.

Question 44

exp

Answer 44

Y = exp(X) returns the exponential ex for each element in array X. For complex elements z = x + iy, it returns the complex exponential

Question 45

log

Answer 45

Y = log(X) returns the natural logarithm ln(x) of each element in array X.

Question 46

polyfit

Answer 46

p = polyfit(x,y,n) returns the coefficients for a polynomial p(x) of degree n that is a best fit (in a least-squares sense) for the data in y. The coefficients in p are in descending powers, and the length of p is n+1

Question 47

meshgrif

Answer 47

p = polyfit(x,y,n) returns the coefficients for a polynomial p(x) of degree n that is a best fit (in a least-squares sense) for the data in y. The coefficients in p are in descending powers, and the length of p is n+1

Question 48

loglog

Answer 48

loglog(Y) plots the columns of Y versus their index if Y contains real numbers. If Y contains complex numbers, loglog(Y) and loglog(real(Y),imag(Y)) are equivalent. loglog ignores the imaginary component in all other uses of this function.

Question 49

• Semilogx

Answer 49

semilogx plot data as logarithmic scales for the x-axis.

Question 50

T = readtable(filename) creates a table by reading column oriented data from a file.

readtable determines the file format from the file extension:

Answer 50

num = xlsread(filename) reads the first worksheet in the Microsoft® Excel® spreadsheet workbook named filename and returns the numeric data in a matrix.

Question 51

sound

Answer 51

sound(y) sends audio signal y to the speaker at the default sample rate of 8192 hertz.

example
sound(y,Fs) sends audio signal y to the speaker at sample rate Fs.

example
sound(y,Fs,nBits) uses nBits bits per sample for audio signal y.

Question 52

beep

Answer 52

beep produces your computer’s default beep sound, if it is enabled.