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 Program Script (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 Code Calculate & 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 Look Especially Handy When Plotting Several Lines on Same Graph Use Help Menu to Find Out More

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