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# Problem Solving MATLAB Part 1 Chapman Book

Q-1. Answer the following questions for the array shown here.

(a) What is the size of array1?

(b) What is the value of array1(1,4)?

(c) What is the size and value of array1(:,1:2:5)?

(d) What is the size and value of array1([1 3],end)?

```clc;
clear all;
close all;

array1 = [0.0 0.5 2.1 -3.5 6.0;
0.0 -1.1 -6.6 2.8 3.4; 2.1 0.1 0.3 -0.4 1.3; 1.1 5.1 0.0 1.1 -2.0];

% (a) What is the size of array1?
size_array1 = size(array1);
fprintf("Size Of Array1 %d By %d\n\n",size_array1);

% (b) What is the value of array1(1,4)?
value = array1(1,4);
fprintf("Value Of Array1(1,4) = %5f\n",value);

% (c) What is the size and value of array1(:,1:2:5)?
array2 = array1(:,1:2:5);
size_array2 = size(array2);
disp('Array2');
disp(array2);
fprintf("Size Of Array2 Is %d By %d\n\n",size_array2);

% (d) What is the size and value of array1([1 3],end)?
array3 = array1([1 3],end);
size_array3 = size(array3);
disp('Array3');
disp([array3]);
fprintf("Size Of Array3 Is %d By %d\n",size_array3);
```

Output

Q-2. Are the following MATLAB variable names legal or illegal? Why?

(a) dog1

(b) 1dog

(c) Do_you_know_the_way_to_san_jose

(d) _help

(e) What’s_up?

```clc;
clear all;
close all;

dog1=1;
1dog=1;
Do_you_know_the_way_to_san_jose=1;
help=1;
What's_up? = 1;
```

Output

a –> valid(number can be in between or at last)

b –> invalid because in matlab variable name cannot start with number

c –> valid(_under scotch is valid)

d –> valid

e –> invalid because ‘s cannot be used

Q-3. Determine the size and contents of the following arrays. Note that the later arrays may depend on the definitions of arrays defined earlier in this exercise.

(a) a = 2:3:8;

(b) b = [a’ a’ a’];

(c) c = b(1:2:3,1:2:3);

(d) d = a + b(2,:);

(e) w = [zeros(1,3) ones(3,1)’ 3:5′];

(f ) b([1 3],2) = b([3 1],2);

(g) e = 1:-1:5;

```clc;
clear all;
close all;

a = 2:3:8;
disp(' a = ')
disp(a);
fprintf("Size Of a Is %d by %d\n",size(a));

b = [a' a' a'];
disp(' b = ')
disp(b);
fprintf("Size Of b Is %d by %d\n",size(b));

c = b(1:2:3, 1:2:3);
disp(' c = ')
disp(c);
fprintf("Size Of c Is %d by %d\n",size(c));

d = a + b(2,:);
disp(' d = ')
disp(d);
fprintf("Size Of d Is %d by %d\n",size(d));

w = [zeros(1,3) ones(3,1)' 3:5'];
disp(' w = ')
disp(w);
fprintf("Size Of w Is %d by %d\n",size(w));

b([1 3],2) = b([3 1],2);
disp(' Updated b = ')
disp(b);
fprintf("Size Of Updated b Is %d by %d\n",size(b));

e = 1:-1:5;
disp(' e = ')
disp(e);
fprintf("Size Of e Is %d by %d\n\n",size(e));
```

Output