Chapter 2 : Numeric, Cell, and Structure Arrays

Question 1

v(:)

Answer 1

represents all the row or oclumn elements of hte vector v

Question 2

v(2:5)

Answer 2

represents the second through fifth elements; that is v(2), v(3), v(4), v(5)

Question 3

A(:,3)

Answer 3

denotes all the elements in the third column of matrix A

Question 4

A(3,:)

Answer 4

denotes all the elements in the thrid row of A

Question 5

A(:,2:5)

Answer 5

denotes all the elements in the second through fifth columns of A

Question 6

A(2:3,1:3)

Answer 6

denotes all the elements in the second and third rows that are also in the first through third columns

Question 7

v=A(:)

Answer 7

creates a vector v consisting of all the columns of A stacked from first to last

Question 8

A(end,:)

A(:,end)

Answer 8

denotes the last row in A

denotes the last column in A

Question 9

sum(A)

Answer 9

sums the elements in each column of the array A and returns a row vector containing the sums

Question 10

what is the command for dot and cross product?

Answer 10

dot(A,B)

cross(A,B)

Question 11

what is the command for finding te roots of a polynomial

Answer 11

roots (a)

Question 12

how do you create a polynomial in matlab?

Answer 12

type in the coefficients in decending order of powers of x. you do not need to type in any variables

Question 13

what is the command to create a polynomial with specific roots?

Answer 13

p = poly([root, root])

Question 14

what is the command for evaluating a polynomial, a , at specific values x

Answer 14

polyval(a,x)

Question 15

what is the command for a graphical display of a cell’s array in the form of a grid?

Answer 15

B = { [#,#] , [#,#] }
or A(1,1) = #
A(1,2) = #
etc
then type
cellplot(A)
cellplot(B)

Question 16

how do you create a structure array?

Answer 16

title.subdivision_name = ‘actual_name’
for a second column type
title(2).subdivision_name = ‘actual_name’