Why MATLAB is used in engineering and science - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a matrix of zeros with 3 rows and 4 columns.

MATLAB

A = zeros([1], 4);

Drag options to blanks, or click blank then click option'

A4

B3

C5

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using the number of columns as the first argument.

The zeros function creates a matrix filled with zeros. The first argument is the number of rows.

2fill in blank

medium

Complete the code to calculate the sine of 45 degrees (in radians).

MATLAB

result = sin([1]);

Drag options to blanks, or click blank then click option'

A45

B90

Cpi/4

Dpi/2

Attempts:

3 left

💡 Hint

Common Mistakes

Using degrees directly without converting to radians.

MATLAB's sin function expects radians. 45 degrees equals pi/4 radians.

3fill in blank

hard

Fix the error in the code to compute the mean of vector v.

MATLAB

average = [1](v);

Drag options to blanks, or click blank then click option'

Amean

Bmax

Clength

Dsum

Attempts:

3 left

💡 Hint

Common Mistakes

Using sum or length instead of mean.

The mean function calculates the average value of elements in a vector.

4fill in blank

hard

Fill both blanks to create a vector x with values from 1 to 10 with step 2.

MATLAB

x = [1]:[2]:10;

Drag options to blanks, or click blank then click option'

A1

B2

C3

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong start or step values.

The colon operator syntax is start:step:end. Here, start is 1 and step is 2.

5fill in blank

hard

Fill all three blanks to create a structure with fields 'name', 'age', and 'score'.

MATLAB

student.[1] = 'Alice'; student.[2] = 20; student.[3] = 95;

Drag options to blanks, or click blank then click option'

Aname

Bage

Cscore

Dgrade

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect field names or typos.

Structures use dot notation to assign values to fields. The fields are 'name', 'age', and 'score'.

Practice

1. Why is MATLAB commonly used by engineers and scientists?

easy

A. Because it simplifies math and data tasks

B. Because it is a web development tool

C. Because it is mainly used for writing novels

D. Because it only works on mobile devices

Solution

1. Step 1: Understand MATLAB's main purpose

   MATLAB is designed to help with math, data analysis, and simulations.

2. Step 2: Match the purpose with the options

   Only Because it simplifies math and data tasks mentions simplifying math and data tasks, which fits MATLAB's use.

3. Final Answer:

   Because it simplifies math and data tasks -> Option A

4. Quick Check:

   MATLAB purpose = Simplify math and data [OK]

Hint: Think about MATLAB's main use in math and data [OK]

Common Mistakes:

• Confusing MATLAB with web or mobile tools
• Thinking MATLAB is for writing text or novels

2. Which of the following is the correct way to create a vector in MATLAB?

easy

A. v = {1 2 3 4};

B. v = (1 2 3 4);

C. v = [1, 2, 3, 4];

D. v = <1 2 3 4>;

Solution

1. Step 1: Recall MATLAB vector syntax

   Vectors are created using square brackets with spaces or commas between elements.

2. Step 2: Check each option

   v = [1, 2, 3, 4]; uses square brackets and commas correctly; others use invalid symbols.

3. Final Answer:

   v = [1, 2, 3, 4]; -> Option C

4. Quick Check:

   Vector syntax = square brackets [OK]

Hint: Remember vectors use square brackets in MATLAB [OK]

Common Mistakes:

• Using parentheses instead of brackets
• Using curly braces which create cell arrays
• Using angle brackets which are invalid

3. What will be the output of this MATLAB code?

t = 0:0.5:2;
y = t.^2;
disp(y);

medium

A. [0 0.25 1 2.25 4]

B. [0 0.5 1 1.5 2]

C. [0 0.25 0.5 0.75 1]

D. [0 1 4 9 16]

Solution

1. Step 1: Understand the vector t

   t = 0:0.5:2 creates [0 0.5 1 1.5 2].

2. Step 2: Calculate y = t.^2 element-wise

   Squaring each element: 0^2=0, 0.5^2=0.25, 1^2=1, 1.5^2=2.25, 2^2=4.

3. Final Answer:

   [0 0.25 1 2.25 4] -> Option A

4. Quick Check:

   Element-wise square = correct output [OK]

Hint: Remember .^ squares each element, not matrix power [OK]

Common Mistakes:

• Confusing element-wise power with matrix power
• Misunderstanding the colon operator range
• Incorrectly calculating squares

4. Identify the error in this MATLAB code snippet:

time = 0:1:5
velocity = [10 20 30 40 50];
acceleration = velocity / time;

medium

A. Missing semicolon after first line

B. Division of vectors with different sizes causes error

C. Using / instead of .* for element-wise division

D. Variable names are invalid

Solution

1. Step 1: Check vector sizes

   time has 6 elements (0 to 5), velocity has 5 elements.

2. Step 2: Understand division operation

   Division of vectors with / expects compatible sizes; dividing by zero or mismatched sizes causes error.

3. Final Answer:

   Division of vectors with different sizes causes error -> Option B

4. Quick Check:

   Vector size mismatch = error [OK]

Hint: Check vector sizes before division [OK]

Common Mistakes:

• Not checking vector sizes before division
• Thinking missing semicolon causes runtime error
• Confusing / with element-wise .* operator

5. You want to simulate the temperature change over time using MATLAB. Which feature makes MATLAB especially suitable for this task?

hard

A. Its use as a word processor for writing reports

B. Its focus on web page design and HTML editing

C. Its limitation to only handle text data

D. Its ability to create interactive plots and run simulations easily

Solution

1. Step 1: Identify simulation needs

   Simulating temperature change requires calculations and visualizing results over time.

2. Step 2: Match MATLAB features

   MATLAB offers easy plotting and simulation tools, making it ideal for this task.

3. Final Answer:

   Its ability to create interactive plots and run simulations easily -> Option D

4. Quick Check:

   Simulation + plotting = MATLAB strength [OK]

Hint: Remember MATLAB excels at simulations and plotting [OK]

Common Mistakes:

• Confusing MATLAB with web or text editing tools
• Thinking MATLAB cannot handle numeric simulations