This document provides an introduction to MATLAB. It discusses that MATLAB is a high-performance language for technical computing that integrates computation, visualization, and programming. It can be used for tasks like math and computation, algorithm development, modeling, simulation, prototyping, data analysis, and scientific graphics. MATLAB uses arrays as its basic data type and allows matrix and vector problems to be solved more quickly than with other languages. The document then provides examples of entering matrices, using basic MATLAB commands and functions, plotting graphs, and writing MATLAB code in M-files.

2. Command Window Command History Workspace Fig: Snap shot of matlab

26. USING THE PLOT COMMAND TO PLOT MULTIPLE CURVES The command: plot(x,y,u,v) plots y versus x and v versus u on the same plot. By default, the computer makes the curves in different colors. The curves can have a specific style by using: plot(x,y,’color_linestyle_marker’,u,v, ’color_linestyle_marker’) More curves can be added.

30. x=[0:0.1:10]; y=500-0.5*9.81*x.^2; xd=[0:10]; yd=[500 495 490 470 430 390 340 290 220 145 60]; plot(x,y,'g',xd,yd,'mo--') xlabel('TIME (s)') ylabel('HEIGHT (m)') title('Height as a Function of Time') legend('Model','Data') axis([0 11 0 600]) text(1,100,'Comparison between theory and experiment') EXAMPLE OF A FORMATTED PLOT WITH TWO CURVES Below is the script file of the falling object plot in lecture 4. Plot y versus x in green, and plot yd versus xd in magenta, circle markers, and dashed line. Creating a vector of time (data) xd Calculated height y for each x Creating a vector of time x Creating a vector of height (data) yd

31. A PLOT WITH TWO CURVES

32. Subplots For example, the command: subplot(3,2, p ) Creates 6 plots arranged in 3 rows and 2 columns. subplot(3,2,1) subplot(3,2,2) subplot(3,2,3) subplot(3,2,5) subplot(3,2,4) subplot(3,2,6)

33. Example: Plot the 3-D surface described by the equation, in the region in the x-y plane from x = -5 to 5 and y = -4 to 4. Step 1) solve the equation for z, (continued on the next slide) 3-D Plotting

34. Step 2) create two vectors x and y . The values of x and y will determine the region in the xy plane over which the surface is plotted. >> x = linspace(-3,3,7); >> y = linspace(-2,2,5); Step 3) Use the meshgrid function to create two matrices, X and Y . We will use these to compute Z . >> [X , Y] = meshgrid(x,y)

35. X = Y =

36. 5- Step 4) compute Z by using the X and Y created by meshgrid , >> R = sqrt(X.^2+Y.^2); >> Z = cos(X).*cos(Y).*exp(-R./4) Z =

37. 5- Step 4) compute Z by using the X and Y created by meshgrid , >> R = sqrt(X.^2+Y.^2); >> Z = cos(X).*cos(Y).*exp(-R./4); Step 5) graph in 3-D by applying the surface function, >> surf(X,Y,Z);