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Plot σ_x vs. r_i

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Step 3: Plot σ_x vs. r_i

Calculate σ_x at O

Essentially, we need to repeat our previous calculation of σ_x at O for a range of r_ivalues. One way to do this is to loop over the previous calculation. There are two types of loops: for and while. Let's check the documentation to see what MATLAB provides for loops. Enter for loop in the search bar and then select for which is the first entry up top. Look at the first example. This shows the format of the for loop. You can often speed up the execution of MATLAB code by replacing for and while loops with vectorized code. That is what we'll do in Step 4. Let's stick it out with slowpoke for loop for now.

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How do we know if the results are right? Let's spot-check the result for ri=1e-2 m against the previous step; this value of ri corresponds to k=6. What is your value of sigma_x(k) for k=6? You can check this from the output or by typing sigma_x(6) at the command line. My value is exactly the same as in Step 2 ... nailed that one! How about you?

Now that we have spot checked our result, add a semi-colon after the sigma_x statement to avoid cluttering up the output.

Plot σ_x vs. r_i

Let's pick MATLAB's brain on how to make a plot.

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Recall that "you can often speed up the execution of MATLAB code by replacing for and while loops with vectorized code". We are into speed, so let's vectorize our program.

Go to Step 4: Plot σ_x vs. r_i:  (Take 2)

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