Anonymous functions in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an anonymous function that squares its input.

MATLAB

square = [1] x^2;

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

A@(x)

Bfunction

Clambda

Ddef

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'function' keyword instead of '@(x)'

Trying to use Python or other language syntax like 'lambda' or 'def'

The @(x) syntax defines an anonymous function in MATLAB that takes x as input.

2fill in blank

medium

Complete the code to create an anonymous function that adds 5 to its input.

MATLAB

addFive = [1] x + 5;

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

A@(x)

Bfunction

Clambda

Ddef

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the '@' symbol

Using other language syntax like 'lambda'

Anonymous functions in MATLAB start with @(x) followed by the expression.

3fill in blank

hard

Fix the error in the anonymous function that multiplies input by 3.

MATLAB

triple = [1] x * 3;

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

Alambda

Bfunction

C@(x)

Ddef

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'function' keyword

Using Python syntax like 'lambda' or 'def'

The correct way to define an anonymous function in MATLAB is with @(x).

4fill in blank

hard

Fill both blanks to create an anonymous function that returns true if input is greater than 10.

MATLAB

isGreaterThanTen = [1] x [2] 10;

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

A@(x)

B==

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using equality operator instead of greater than

Omitting the '@(x)' part

The anonymous function starts with @(x) and uses the greater than operator > to compare.

5fill in blank

hard

Fill all three blanks to create an anonymous function that returns true if input is between 5 and 15 (inclusive).

MATLAB

isBetween = [1] x [2] 5 && x [3] 15;

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

A@(x)

B>=

C<=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using strict greater than or less than instead of inclusive operators

Omitting the '@(x)' syntax

The function uses @(x) to define the anonymous function, and checks if x is greater than or equal to 5 and less than or equal to 15.

Practice

1. What is an anonymous function in MATLAB?

easy

A. A quick, unnamed function created using the '@' symbol.

B. A function saved in a separate file with a name.

C. A function that can only be used inside loops.

D. A function that requires no input arguments.

Solution

1. Step 1: Understand the definition of anonymous functions

   Anonymous functions in MATLAB are small, unnamed functions created using the '@' symbol.

2. Step 2: Compare options with the definition

   A quick, unnamed function created using the '@' symbol. correctly describes anonymous functions as quick, unnamed functions created with '@'. Other options describe named functions or incorrect properties.

3. Final Answer:

   A quick, unnamed function created using the '@' symbol. -> Option A

4. Quick Check:

   Anonymous function = unnamed function with '@' [OK]

Hint: Look for '@' symbol to identify anonymous functions [OK]

Common Mistakes:

• Confusing anonymous functions with regular named functions
• Thinking anonymous functions must have no inputs
• Assuming anonymous functions are saved in separate files

2. Which of the following is the correct syntax to create an anonymous function that squares its input x?

easy

A. f = @(x) x^2;

B. f = function(x) x^2;

C. f = @x x^2;

D. f = (x) => x^2;

Solution

1. Step 1: Recall MATLAB anonymous function syntax

   The correct syntax uses '@(args) expression;' so for squaring x, it is '@(x) x^2;'.

2. Step 2: Check each option

   f = @(x) x^2; matches the correct syntax. f = function(x) x^2; uses incorrect keyword 'function'. f = @x x^2; misses parentheses. f = (x) => x^2; uses arrow syntax from other languages.

3. Final Answer:

   f = @(x) x^2; -> Option A

4. Quick Check:

   Anonymous function syntax = @(args) expression [OK]

Hint: Remember '@(x) expression;' for anonymous functions [OK]

Common Mistakes:

• Omitting parentheses around input arguments
• Using 'function' keyword inside anonymous function
• Using arrow syntax from other languages

3. What is the output of the following MATLAB code?

f = @(x) x + 5;
result = f(10);
disp(result);

medium

A. 5

B. 10

C. 15

D. Error

Solution

1. Step 1: Understand the anonymous function definition

   The function f adds 5 to its input x.

2. Step 2: Calculate the function output for input 10

   f(10) = 10 + 5 = 15.

3. Final Answer:

   15 -> Option C

4. Quick Check:

   10 + 5 = 15 [OK]

Hint: Apply input to expression inside @(x) function [OK]

Common Mistakes:

• Confusing input and output values
• Expecting function to multiply instead of add
• Thinking anonymous functions cause errors without file

4. Identify the error in this MATLAB anonymous function:

g = @x x^2 + 3;

medium

A. Anonymous functions cannot use addition.

B. Missing parentheses around input argument x.

C. The '@' symbol is not allowed here.

D. The function must be saved in a separate file.

Solution

1. Step 1: Check anonymous function syntax

   Anonymous functions require parentheses around input arguments, like '@(x)'.

2. Step 2: Identify the syntax error

   The code uses '@x' without parentheses, which is invalid syntax.

3. Final Answer:

   Missing parentheses around input argument x. -> Option B

4. Quick Check:

   Anonymous function input must be in parentheses [OK]

Hint: Always use @(input) with parentheses [OK]

Common Mistakes:

• Omitting parentheses around inputs
• Thinking '@' can be used without parentheses
• Believing anonymous functions need separate files

5. You want to create an anonymous function h that takes two inputs x and y and returns x squared plus y cubed. Which is the correct way to write this?

hard

A. h = @(x y) x^2 + y^3;

B. h = @(x,y) x^2 * y^3;

C. h = @(x,y) (x^2), (y^3);

D. h = @(x,y) x^2 + y^3;

Solution

1. Step 1: Understand multiple inputs in anonymous functions

   Multiple inputs are separated by commas inside parentheses: @(x,y).

2. Step 2: Check the expression for correct operations

   The function should return x squared plus y cubed, so use '+' operator, not '*'.

3. Final Answer:

   h = @(x,y) x^2 + y^3; -> Option D

4. Quick Check:

   Multiple inputs use commas; '+' adds results [OK]

Hint: Separate inputs with commas and use correct operators [OK]

Common Mistakes:

• Omitting commas between inputs
• Using wrong operators like multiplication instead of addition
• Trying to separate expressions with commas outside parentheses