EGR 103/Fall 2009/Questions

Lab 5

• I am making a graph for NormDist.m as part of Lab 5, but I cannot get NormDist to accept a non-square matrix of z values. It treats linspace(-4, 4, 100) as a 100 x 1 matrix. Any hints for how I can graph NormDist? Mjc43 13:46, 12 September 2009 (EDT)
  • It's treating it as a 1 x 100 matrix - and that is correct; be sure to use .* and ./ and .^ in your calculation and it will be fine. DukeEgr93 14:42, 12 September 2009 (EDT)

• On Problem 5.4.3, I typed in the Manning equation as

  U = (sqrt(S)./n)*((B.*H)/(B+2.*H))^(2/3)
  

  which failed to produce a graph. What is the reason for this?—Preceding unsigned comment added by Xyz2006tor (talk • contribs)
  • That just calculates a value - you have to use the plot command to create a graph. DukeEgr93 00:40, 17 September 2009 (EDT)

• how do I find the most displacement for a million values? I've run it for like 25 minutes and matlab is still busy. Ruobling 17:09, 17 September 2009 (EDT)
  • The min command certainly should not take that long, even for 1 million values... Is it waiting for you to hit return? DukeEgr93 15:25, 19 September 2009 (EDT)

• For lab 6, I gave code that clearly defined a function for input x, I can run the function from my command window, but when I run the .m file, it say that variable x is undefined. I look at other examples, and they appear identical without having this problem. What am I doing wrong? Mjc43 00:14, 28 September 2009 (EDT)