Function definition syntax in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a function named 'add' that takes two inputs.

MATLAB

function result = [1](a, b)
    result = a + b;
end

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

Aadd

Bsum

Cplus

Dcalculate

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different function name than the one intended.

Forgetting to write the function name after 'function'.

The function name must match the name after the 'function' keyword. Here, 'add' is the correct function name.

2fill in blank

medium

Complete the code to define a function that returns the square of input x.

MATLAB

function y = [1](x)
    y = x^2;
end

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

Asquare

Bpower

CsquareRoot

Dmultiply

Attempts:

3 left

💡 Hint

Common Mistakes

Using a misleading function name like 'squareRoot' when squaring.

Choosing a generic name like 'multiply' that doesn't specify the operation.

The function name 'square' clearly indicates it returns the square of x.

3fill in blank

hard

Fix the error in the function header to correctly define a function named 'greet' with input 'name'.

MATLAB

function [1](name)
    disp(['Hello, ', name, '!']);
end

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

Ahello

Bgreeting

CsayHello

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different function name than 'greet'.

Omitting the function keyword or parentheses.

The function name must be 'greet' to match the intended function definition.

4fill in blank

hard

Fill both blanks to define a function 'multiply' that takes inputs 'a' and 'b' and returns their product.

MATLAB

function [1] = multiply([2], b)
    [1] = a * b;
end

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

Aresult

Ba

Coutput

Dx

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent variable names between function header and body.

Forgetting to name the output variable.

The output variable is 'result' and the first input variable is 'a'.

5fill in blank

hard

Fill all three blanks to define a function 'maxValue' that returns the maximum of two inputs 'x' and 'y'.

MATLAB

function [1] = maxValue([2], [3])
    if [2] > [3]
        [1] = [2];
    else
        [1] = [3];
    end
end

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

AmaxVal

Bx

Cy

DmaxValue

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same name for output and function name.

Mismatching input variable names in the function header and body.

The output variable is 'maxVal', inputs are 'x' and 'y', and the function compares x and y to return the maximum.

Practice

1. Which of the following correctly describes the purpose of a function in MATLAB?

easy

A. To run MATLAB without installing it

B. To store data permanently on the computer

C. To create reusable blocks of code that perform specific tasks

D. To display graphics on the screen

Solution

1. Step 1: Understand what functions do

   Functions are designed to perform specific tasks repeatedly without rewriting code.

2. Step 2: Match purpose with options

   Only To create reusable blocks of code that perform specific tasks describes reusable code blocks, which is the main purpose of functions.

3. Final Answer:

   To create reusable blocks of code that perform specific tasks -> Option C

4. Quick Check:

   Function purpose = reusable code [OK]

Hint: Functions are for reusable code blocks [OK]

Common Mistakes:

• Confusing functions with data storage
• Thinking functions display graphics by default
• Assuming functions run MATLAB itself

2. Which of the following is the correct syntax to define a function named addNumbers that takes two inputs a and b and returns their sum c?

easy

A. function addNumbers = c(a, b)

B. function c = addNumbers(a, b)

C. def addNumbers(a, b):

D. func c(a, b) = addNumbers

Solution

1. Step 1: Recall MATLAB function syntax

   MATLAB functions start with the keyword 'function', then output(s), '=', function name, and input(s) in parentheses.

2. Step 2: Check each option

   function c = addNumbers(a, b) matches this syntax exactly. Options A, B, and D use incorrect keywords or order.

3. Final Answer:

   function c = addNumbers(a, b) -> Option B

4. Quick Check:

   function keyword + output = name(inputs) [OK]

Hint: Start with 'function', then output = name(inputs) [OK]

Common Mistakes:

• Using Python syntax like 'def'
• Placing function name before output incorrectly
• Using wrong keywords like 'func'

3. What will be the output of the following MATLAB function call?

function y = squareNum(x)
    y = x^2;
end

result = squareNum(4); disp(result);

medium

A. Error: Undefined function

B. 8

C. 4

D. 16

Solution

1. Step 1: Understand the function behavior

   The function squares the input number x by calculating x^2.

2. Step 2: Calculate the output for input 4

   4 squared is 4 * 4 = 16.

3. Final Answer:

   16 -> Option D

4. Quick Check:

   4 squared = 16 [OK]

Hint: Square input number to get output [OK]

Common Mistakes:

• Confusing ^ with multiplication
• Expecting addition instead of power
• Assuming function is undefined

4. Identify the error in the following MATLAB function definition:

function result = multiply(a, b)
result = a * b
end

medium

A. Missing semicolon after the multiplication statement

B. Function name does not match the file name

C. Incorrect use of the multiplication operator

D. Missing 'function' keyword

Solution

1. Step 1: Check syntax inside the function

   MATLAB statements should end with a semicolon to suppress output; here, it's missing after 'result = a * b'.

2. Step 2: Verify other parts

   The function keyword is present, the operator is correct, and file name matching is not shown but assumed correct.

3. Final Answer:

   Missing semicolon after the multiplication statement -> Option A

4. Quick Check:

   Statements need semicolon [OK]

Hint: End statements with semicolon to avoid errors [OK]

Common Mistakes:

• Forgetting semicolons after statements
• Assuming multiplication operator is wrong
• Ignoring file name and function name match

5. You want to create a MATLAB function named convertToFahrenheit that takes a Celsius temperature input and returns the Fahrenheit equivalent. Which of the following is the correct complete function definition?

hard

A. function F = convertToFahrenheit(C)
F = (C * 9/5) + 32;
end

B. function convertToFahrenheit = F(C)
F = (C + 32) * 9/5;
end

C. function F = convertToFahrenheit(C)
F = (C - 32) * 5/9;
end

D. function F = convertToFahrenheit(C)
F = C * 5/9 + 32;
end

Solution

1. Step 1: Recall the formula for Celsius to Fahrenheit

   The correct formula is Fahrenheit = (Celsius * 9/5) + 32.

2. Step 2: Check each function definition

   function F = convertToFahrenheit(C) F = (C * 9/5) + 32; end uses the correct formula and syntax. Options A, C, and D have wrong formulas or incorrect output variable assignment.

3. Final Answer:

   function F = convertToFahrenheit(C) F = (C * 9/5) + 32; end -> Option A

4. Quick Check:

   Celsius to Fahrenheit formula = (C * 9/5) + 32 [OK]

Hint: Use correct formula: F = (C * 9/5) + 32 [OK]

Common Mistakes:

• Mixing Celsius to Fahrenheit with Fahrenheit to Celsius formula
• Swapping output and function name
• Missing semicolons or wrong operators