Help system and documentation in MATLAB

Introduction

The help system in MATLAB shows you how to use commands and functions. Documentation explains what each part does so you can learn and fix problems.

You want to know what a MATLAB function does before using it.

You need examples to understand how to write a command.

You want to find out what inputs a function needs.

You want to check what outputs a function gives.

You want to learn about MATLAB features without searching online.

Syntax

MATLAB

help function_name

doc function_name

help shows a short explanation in the command window.

doc opens a detailed help page with examples in the MATLAB Help browser.

Examples

Shows a short description of the plot function in the command window.

MATLAB

help plot

Opens the full documentation page for plot with examples and details.

MATLAB

doc plot

Displays how to use the mean function to find averages.

MATLAB

help mean

Sample Program

This program shows how to get quick help on the sum function using help. The doc command opens a detailed help window but does not print output here.

MATLAB

% Use help to learn about the sum function
help sum

% Use doc to open detailed documentation for sum
% (This opens a window, so no output here)

Important Notes

You can type help or doc followed by any function name to get help.

Use help for quick info and doc for detailed explanations and examples.

Documentation helps you learn MATLAB faster and avoid mistakes.

Summary

The help command shows short explanations in the command window.

The doc command opens detailed documentation with examples.

Use these tools whenever you want to understand or learn MATLAB functions.

Practice

1. What does the help command do in MATLAB?

easy

A. Shows a short explanation of a function in the command window

B. Opens a detailed graphical documentation page

C. Runs the function with default parameters

D. Edits the function's source code

Solution

1. Step 1: Understand the purpose of help

   The help command is designed to show a brief explanation or summary of a MATLAB function directly in the command window.

2. Step 2: Compare with other options

   doc opens detailed documentation, running or editing functions is unrelated to help.

3. Final Answer:

   Shows a short explanation of a function in the command window -> Option A

4. Quick Check:

   help shows short explanation [OK]

Hint: Remember: help = quick info in command window [OK]

Common Mistakes:

• Confusing help with doc
• Thinking help runs the function
• Assuming help edits code

2. Which of the following is the correct way to open detailed documentation for the function plot?

easy

A. open plot

B. help plot

C. doc plot

D. run plot

Solution

1. Step 1: Identify the command for detailed documentation

   The doc command opens the detailed documentation page with examples and explanations.

2. Step 2: Check other options

   help shows short info, open and run are not used for documentation.

3. Final Answer:

   doc plot -> Option C

4. Quick Check:

   doc opens detailed docs [OK]

Hint: Use doc for detailed help with examples [OK]

Common Mistakes:

• Using help instead of doc for detailed info
• Trying to use open or run commands
• Forgetting to type the function name after doc

3. What will be the output of the command help sum in MATLAB?

medium

A. It will execute the sum function on the current workspace variables

B. It will display a brief description of the sum function in the command window

C. It will open the full documentation page for sum in a separate window

D. It will show an error because help cannot be used with sum

Solution

1. Step 1: Understand what help sum does

   The help command shows a short explanation of the specified function, here sum, in the command window.

2. Step 2: Eliminate incorrect options

   doc opens full docs, help does not execute functions or cause errors for built-in functions.

3. Final Answer:

   It will display a brief description of the sum function in the command window -> Option B

4. Quick Check:

   help shows brief info [OK]

Hint: help shows short info, doc shows full docs [OK]

Common Mistakes:

• Confusing help with doc
• Expecting help to run the function
• Thinking help causes errors for built-in functions

4. You typed helpplot in MATLAB but got an error. What is the likely problem?

medium

A. You forgot to put a space between help and the function name

B. The help command does not work for plotting functions

C. You need to use docplot instead

D. The function plot does not exist in MATLAB

Solution

1. Step 1: Analyze the command helpplot

   This is a single word, so MATLAB looks for a function named helpplot, which does not exist.

2. Step 2: Correct usage of help

   The correct syntax is help plot with a space to ask for help on the plot function.

3. Final Answer:

   You forgot to put a space between help and the function name -> Option A

4. Quick Check:

   Use space after help [OK]

Hint: Always put space between help and function name [OK]

Common Mistakes:

• Typing help and function name without space
• Assuming help doesn't work for plot
• Trying docplot instead of doc plot

5. You want to learn how to use the fft function with examples and detailed explanations. Which command should you use and why?

hard

A. Use edit fft to read the source code and understand usage

B. Use help fft because it shows detailed examples

C. Use run fft to execute the function and see results

D. Use doc fft because it opens full documentation with examples

Solution

1. Step 1: Identify the need for detailed explanations and examples

   Detailed explanations and examples are found in the full documentation, not in the short help text.

2. Step 2: Choose the correct command

   doc fft opens the full documentation page with examples, while help fft shows only brief info.

3. Step 3: Understand why other options are incorrect

   run fft executes the function, edit fft opens source code which may not be helpful for beginners.

4. Final Answer:

   Use doc fft because it opens full documentation with examples -> Option D

5. Quick Check:

   doc = detailed docs with examples [OK]

Hint: Use doc for full docs and examples, help for quick info [OK]

Common Mistakes:

• Using help expecting detailed examples
• Trying to run function to learn usage
• Editing source code instead of reading docs