1.3.2 - Using MATLAB as a calculator
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Introduction to MATLAB as a Calculator
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Welcome, class! Today, we will learn how to use MATLAB as a basic calculator. It will enhance your understanding of mathematical operations through practical examples. Who here has used a calculator before?
I have! But how is it different from the calculator on my phone?
Great question! While regular calculators can handle basic arithmetic, MATLAB is designed for more complex computations and allows you to store results in variables. Let's try typing `1 + 2 * 3`. What do you think the answer will be?
I think it should be 9, right?
Actually, it's 7! Because MATLAB follows the order of operations where multiplication comes before addition. This is a good point to remember!
Working with Variables
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Now that we know how to type expressions, let's learn how to assign these results to variables. For example, if we type `x = 1 + 2 * 3`, what will happen?
Will x store the value of 7?
Exactly! You can use `x` later for other calculations. If I then compute `4 * x`, what do you expect the answer will be?
It should be 28, right?
Correct! That's 4 times 7. Remember, using variables helps keep your calculations more organized.
Understanding Operator Precedence
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We have touched on operator precedence; let's clarify this further. Why do you think parentheses are essential when executing calculations?
They help tell MATLAB the order to perform the calculations!
Exactly! For instance, `1 + 2 * 3` gives 7, but `(1 + 2) * 3` gives 9. This distinction is crucial to ensuring accurate results.
What about if we write a complex expression without parentheses?
Good point! Always remember to clarify your expressions with parentheses to avoid mistakes. Let's practice with a few more examples!
Displaying Results and Using Commands
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Let's discuss how we can control how results appear. If I want to see more than four decimal places, what command might I use?
You could use the 'format long' command!
That's correct! Using `format long` allows us to see more precision in our results. Also, to clear the memory, which command is best?
Is it `clear`?
Yes! Cleansing the workspace is essential to avoid any confusion with variable names. Remember to use `who` to check your variables too!
Introduction & Overview
Read summaries of the section's main ideas at different levels of detail.
Quick Overview
Standard
In this section, readers learn to use MATLAB for quick and interactive calculations. Key operations include handling arithmetic expressions, variables, default outputs, and operator precedence, alongside useful commands for clearer results and managing the workspace.
Detailed
Using MATLAB as a Calculator
In this section, we explore the fundamentals of utilizing MATLAB as a calculator. MATLAB can effectively handle arithmetic operations, allowing users to perform simple calculations directly in the Command Window.
Key Concepts:
-
Typing Expressions: Users start by typing a mathematical expression at the prompt (>>). For example, entering
1+2*3will yield an output of 7. If an output variable isn't specified, MATLAB assigns the value to a default variable namedans. -
Defining Variables: To create a variable, users can assign the result of an expression to a variable name, like
x = 1+2*3, which means x now contains the value 7. - Operators: This section also lists fundamental arithmetic operators such as addition (+), subtraction (-), multiplication (*), and division (/), which are used for mathematical calculations.
-
Operator Precedence: Understanding the precedence of operations is crucial when writing expressions. For instance,
1+2*3equals 7, but(1+2)*3equals 9, showcasing how parentheses change the order of operations. -
Displaying Results: MATLAB defaults to showing results with four decimal places but allows users to change the display settings using the
formatcommand, for example,format longto see more significant digits. -
Managing Workspace: Users are encouraged to clear variables using the
clearcommand to avoid potential overwrites and keep track of variables using commands likewhoandwhos.
By understanding these basic operations, users can effectively perform calculations and manage their variables in MATLAB.
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Basic Calculation
Chapter 1 of 3
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Chapter Content
As an example of a simple interactive calculation, just type the expression you want to evaluate. Let’s start at the very beginning. For example, let’s suppose you want to calculate the expression, 1+2*3. You type it at the prompt command (>>) as follows:
>> 1+2*3
The output will be:
ans = 7
Detailed Explanation
In MATLAB, performing calculations is straightforward. You simply type in the mathematical expression you want to evaluate at the command prompt (>>). For instance, if you want to calculate '1 + 2 multiplied by 3', you enter 1 + 2*3. MATLAB processes this expression and returns the result, which in this case is 7. The 'ans' signifies the answer, and it is a default variable created by MATLAB to store results when you do not assign one explicitly.
Examples & Analogies
Think of it like a calculator where you just input an expression, and it instantly computes the answer. For instance, if you're at a coffee shop and you want to know how much you'll spend if you order one coffee for $1, two donuts for $2 each, you might say, '1 + 2*2', and the cashier computes it right away, giving you the total.
Using Variables
Chapter 2 of 3
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Chapter Content
You will have noticed that if you do not specify an output variable, MATLAB uses a default variable ans, short for answer, to store the results of the current calculation. Note that the variable ans is created (or overwritten, if it already existed). To avoid this, you may assign a value to a variable or output argument name. For example,
>> x = 1+2*3 x = 7
Detailed Explanation
When you perform calculations in MATLAB, it automatically stores the result in a variable called 'ans'. However, if you want to reference this result later, it's better to assign it to a variable of your choice. For instance, if you assign the result of '1 + 2*3' to the variable 'x' using x = 1 + 2*3, then you can use 'x' for further calculations without losing the value. This makes your work more organized and clearer.
Examples & Analogies
Imagine you are cooking and measuring ingredients. Instead of just writing down the result every time you measure (like how MATLAB stores 'ans'), you can write 'sugar = 2 cups' on your recipe paper. Later, if a recipe calls for twice the amount, you can simply say, '2 * sugar', instead of having to re-measure it.
Arithmetic Operators
Chapter 3 of 3
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Chapter Content
Before we conclude this minimum session, Table 1.1 gives the partial list of arithmetic operators:
| Symbol | Operation | Example |
|---|---|---|
| + | Addition | 2+3 |
| − | Subtraction | 2−3 |
| * | Multiplication | 2*3 |
| / | Division | 2/3 |
Detailed Explanation
MATLAB supports various arithmetic operations that can be performed using specific symbols. The table lists these operations: addition (+), subtraction (−), multiplication (*), and division (/). Understanding these operators is crucial because they form the basis for all calculations you will perform in MATLAB. Using these symbols correctly will allow you to construct complex expressions.
Examples & Analogies
Think of the arithmetic operators as tools in a toolbox. Just like a carpenter uses a hammer to drive nails and a saw to cut wood, in programming with MATLAB, you use these operators to build your mathematical expressions. Each tool serves a specific purpose, and knowing how to use them effectively makes you a better 'builder' in your calculations.
Key Concepts
-
Typing Expressions: Users start by typing a mathematical expression at the prompt (>>). For example, entering
1+2*3will yield an output of 7. If an output variable isn't specified, MATLAB assigns the value to a default variable namedans. -
Defining Variables: To create a variable, users can assign the result of an expression to a variable name, like
x = 1+2*3, which means x now contains the value 7. -
Operators: This section also lists fundamental arithmetic operators such as addition (+), subtraction (-), multiplication (*), and division (/), which are used for mathematical calculations.
-
Operator Precedence: Understanding the precedence of operations is crucial when writing expressions. For instance,
1+2*3equals 7, but(1+2)*3equals 9, showcasing how parentheses change the order of operations. -
Displaying Results: MATLAB defaults to showing results with four decimal places but allows users to change the display settings using the
formatcommand, for example,format longto see more significant digits. -
Managing Workspace: Users are encouraged to clear variables using the
clearcommand to avoid potential overwrites and keep track of variables using commands likewhoandwhos. -
By understanding these basic operations, users can effectively perform calculations and manage their variables in MATLAB.
Examples & Applications
Example: To calculate 1 + 2 * 3, input '1 + 2 * 3' in the MATLAB Command Window; the output is 7.
Example: Assigning a result: if we type 'x = 1 + 2 * 3', 'x' now holds the value 7 for further calculations.
Memory Aids
Interactive tools to help you remember key concepts
Rhymes
MATLAB's tasks are never slow, just type it out and watch it flow.
Stories
Imagine you have a magic box called MATLAB. Whatever number you input inside can be manipulated and saved, just like a wizard using spells.
Memory Tools
PEAR: Precedence, Expressions, Assignment, Results.
Acronyms
VAMP
Variables
Arithmetic
MATLAB
Precedence.
Flash Cards
Glossary
- MATLAB
A high-performance language for technical computing, primarily used for matrix calculations and engineering applications.
- ans
The default variable used in MATLAB to store the result of operations when no specific variable is assigned.
- Variable
A storage location paired with a name that contains data that can change during program execution.
- Operator Precedence
The rules that define the order in which different operations within an expression are processed.
- format command
A command used to change the display format of numbers in MATLAB.
Reference links
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