basic MATLAB operations

Question 1

How would you wirte a first step last operation?

Answer 1

variable=[first:step:last]

Question 2

Form a row vector

Answer 2

a=[2 3 5]

Question 3

Form a column vector

Answer 3

b=[3;1;8]

Question 4

Form a 2x2 matrix

Answer 4

c=[1 2;7 8]

Question 5

Size of a vector a

Answer 5

size(a)

Question 6

Size of row of vector a

Answer 6

size(a,1)

Question 7

Size of column of vector a

Answer 7

siza(a,2)

Question 8

absolute function

Answer 8

abs

Question 9

natural logorithim

Answer 9

log

Question 10

What does A(4,:) show

Answer 10

all elemnts in 4th row of matrix A

Question 11

What does A([1 3],[2 4]) show

Answer 11

elements in rows 1&3, columns 2&4

Question 12

How to plot a graph (2 steps)

Answer 12

1) define graph f(x)=
2) fplot(f, [-1:1]):

Question 13

How would you write a linspace operation?

Answer 13

a=linspace(first,last,N)

Question 14

create an array of all zeros

Answer 14

z=zeros(m,n)

Question 15

create an array of all ones

Answer 15

o=ones(m,n)

Question 16

create an array of random numbers

Answer 16

r=rand(m,n)

Question 17

How to clear window (keeps memory)

Answer 17

clc

Question 18

Write an identity matrix (ixi)

Answer 18

a=eye(i)

Question 19

How to see all variables

Answer 19

whos

Question 20

Overwriting arrays
Part of a matrix replaced by an identity matrix B

Answer 20

part needing replacing = new part
A(3:5,2:4)=B

Question 21

What are semicolons used for?

Answer 21

Supresses working out, code is still run but output stored in workplace

Question 22

for ones,zeros,rands and eye all ixi matrices can be represented similiary, how?

Answer 22

A=” “(i)

Question 23

Sidenote!!!!!

Answer 23

remember to name variables!!!!!!!!!!!!!!!

Question 24

Sidenote 2!!!!

Answer 24

arrays need square brackets!!!!!

Question 25

Sidenote 3!!!!!!!

Answer 25

rand,zeros,ones need normal brackets!!!!!