Category Archives: Assignments

Exam 3 Grades are posted, and SPECIAL OFFER

Posted on May 16, 2015 by | Leave a comment

Hi everyone,

The grades for Exam 3 are posted on the Grades page (email me if you have forgotten the password).

This exam covered a great deal of material and, while overall grades were comparable to the first exam, I’m sure not everyone did as well as they would have liked.  You may improve your score on the exam by completing the Special Offer below.

Let me know if you have any questions, and best of luck with your studying!
Prof. Reitz

Exam 3 Special Offer – earn bonus points.  You can improve your grade on the exam, by doing the following:

  1. Choose ONLY ONE problem in which you did NOT earn full points.  You are working to earn back (some of ) the points you missed on this problem.
  2. Do the problem over, neatly and completely, start to finish, on a separate sheet of paper.
    1. Don’t forget your name, the date, and the problem number.
  3. On the same sheet, write a short statement (one or two complete sentences) explaining your mistake(s) – the purpose is to let me know that you understand what you did wrong.
  4. Hand in your original exam and your corrected problem and explanation, stapled together, in class on Thursday (the day of the final exam).
  5. Bonus points will be added to your Exam 3 score based on the number of points you missed on the chosen problem,  the accuracy of your corrections and explanation, and your overall grade on the exam.  Bonus points are limited as follows:
    1. If you received less than 60% on the exam, you can earn a maximum of 20 bonus points.
    2. If you received between 60% – 69% on the exam, you can earn a maximum of 15 bonus points.
    3. If you received between 70% – 79% on the exam, you can earn a maximum of 10 bonus points.
    4. If you received between 80% – 89% on the exam, you can earn a maximum of 5 bonus points.
    5. If you received between 90% or more on the exam, you can earn a maximum of 2 bonus points.

 

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WeBWorK 12-day grace period

Posted on May 5, 2015 by | Leave a comment

Hi everyone,

I have re-opened all of your past WeBWorK assignments (except Assignment 16, which is due on Tuesday) to give you the opportunity to complete any unfinished problems.  They will close again on Sunday, May 17th, at midnight.

This is a pretty seriously awesome opportunity to improve your score in the class.

Remember, completing 80% of all WeBWorK problems gives you full credit for webwork – anything more than that is extra credit.

Happy WeBWorKing,
Prof. Reitz

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WeBWorK #11b: Overdamped, Underdamped, and Critically Damped

Posted on April 5, 2015 by | Leave a comment

Hi everyone,

As you work through the assignment on Circuits, you will come across questions about damping, and you may notice that we never spoke about this in class.  Figuring out whether a circuit is over-, under- or critically damped is straightforward, and depends on the discriminant of the characteristic equation — the discriminant is the part under the radical sign when you use the quadratic formula (it controls the number and type of solutions to the quadratic equation):

The Discriminant = b^2-4ac

  • Under-damped: Discriminant < 0  (the characteristic equation has two complex roots)
  • Critically Damped: Discriminant = 0 (the characteristic equation has a repeated root)
  • Over-damped: Discriminant > 0 (the characteristic equation has two distinct real roots)

But that’s cheating!  What does damping actually mean?

Great question!  We will not discuss damping in detail in this class, but if you work with electrical circuits this is a concept you will run into often.  Take a look here for a basic overview:  http://en.wikipedia.org/wiki/Damping

Hope your Spring Break is going well,
Prof. Reitz

 

 

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WeBWorK #9 UPDATE

Posted on April 2, 2015 by | Leave a comment

Hi everyone,

Just a quick update – a few students had reported issues with some of the later problems in WeBWorK #9 (e.g. that the system would not accept a correct answer).  These problems have been resolved, and the problems should work correctly now – go ahead and try them again.  Carefully doublecheck the question to make sure the numbers have not changed before you proceed.

As a reminder, this assignment is due on Tuesday, 4/14.

Have a wonderful Spring Break,
Prof. Reitz

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WeBWorK madness! — Assignment #9 extended to April 14th

Posted on April 1, 2015 by | 3 comments

Hi everyone,

I know you are all working very hard on the WeBWorK assignment #9.  As you have probably discovered:

  1. the problems can be quite long (especially the last couple!)
  2. a few students have run into WeBWorK bugs that incorrectly mark correct answers as “wrong” (I am working to resolve these currently, and hope to have them worked out in the next few days)

Because of this, I have extended this assignment until after Spring Break – it is now due (along with WeBWorK #11b) at the end of the day on Tuesday, April 14th.  Your focus right now should be preparing for the exam on Thursday – good luck!

Prof. Reitz

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WeBWorK extension

Posted on March 24, 2015 by | Leave a comment

WeBWorK assignments #6, 7, 8, formerly due tonight, have been extended by two days.  They are now due this Thursday, 3/26, at midnight.

Regards,
Prof. Reitz

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Euler’s Method Exercises

Posted on March 13, 2015 by | 1 comment

Hi everyone,

Here are some examples of Euler’s Method problems for you to try.  These are for practice only, they will not be collected.
NOTE: The first example is the one we solved in class on Thursday – I’m including it here for your reference.

Questions? Problems? Leave a comment on this post and I’ll respond here.

Example 1.  Given the initial value problem \frac{dy}{dt} = 3-2t-0.5y with y(0)=1, approximate the value of y(1).  Use 5 steps.

Example 2.  Consider y' = y \sin{t} -1.  Suppose y(0)=2.  What is y(3)?  Use a step size of h=0.5.

Example 3. If y'=\frac{x-4}{x-y+1}, use Euler’s method with 4 steps to approximate y(8) for the particular solution satisfying y(3)=3

Example 4.  Given \frac{dy}{dt}=e^\frac{t^2}{y^2+1} - y with y(-0.82)=0.97, estimate the value of y(1.28) using 6 steps.

Solutions to these examples are provided here for your reference – if you notice an error, please let me know by leaving a comment below (or sending an email).

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