MCE 372 Engineering Analysis

MATLAB Review

MATLAB – What Is It ? Where Is It?

Name is from matrix laboratory Powerful tool for

– Computation and visualization of engineering, science and mathematics

– Communication of ideas– Programming:

Built-in editor, debugger, and help Many predefined functions (grouped in toolboxes) Interpreted or compiled programs

Located on all ECC PC’s & in many department facilities

How Do We Want To Use MATLAB

In This Course?

Write Simple MATLAB Programs to Do the Following:

- Perform Particular Calculations

- Display/Plot Results for Interpretation

Creating Your Own ProgramScript (m-file) Concept

M-file is a collection of MATLAB commands – Can be re-executed – Is easily changed/modified, transferred or e-mailed

File format: Name.m Commands are executed one by one sequentially

– File is executed by typing its name (without .m)– Results appear in the command window (or use ; )

Can be created using any text editor, but is most easily developed in MATLAB Editor Window

Boot Up Default MATLAB Window

Help menu provides answers to most questions

Opens Editor Window to create new program

In this window: - type & edit commands- test & run program- save work when finished

Demo MATLAB CodeCalculate & Plot Equation: y=2x+30x2-2x3

Dot needed for element-by-element operation

Semicolon used to suppress output to Command Window – commonly desired

Plotting Line Specifiers

Line Specifiers Change the LookEspecially Handy When Plotting Several Lines on Same GraphUse Help Menu to Find Out More

Example Code% MCE 372 Demo Program% Make Multiple Plots on Same Axes with Legendsclc;clear all;clfx=0:0.1:10;y1=2*x+30*x.^2;y2=10*x.^3;y3=200*x% Plot all functions on same axesplot(x,y1,'k','linewidth',2)hold on;grid onplot(x,y2,'b','linewidth',2)plot(x,y3,'r','linewidth',2)xlabel('x');ylabel('y')title('MCE 372 Demo Plot')legend('y1','y2','y3')

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MCE 372 Demo Plot

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