Lecture 4/30/20

Slides 4/30/20

various communications....

Hello Professor,
I was wondering if you are going to post the video lecture of Thursday's class before the exam on Tuesday. Thank you and hope to hear from you soon.

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1. Stop giving my your id#. Really. I don't need it, I can't use it, it's your private information and email is not a private nor secure medium.

2. I thought I'd posted the video on the blog already on Thursday after class, and then walked away, but instead it looks like Blogger kicked it out for too large a file size.  It's there now.

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Good morning, I was wondering if the test will be taking place this upcoming Tuesday or Thursday. Also, will you be posting the review session on the website?
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Definitely Tuesday. See the answer above.

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Good afternoon sir, Can you please provide us with the information about exam 3 and final. Also about the syllabus coming in the exam. Thanking you
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Exam 3 will be on Tuesday in class.  Webcams must be turned on at all times. The final exam will be as scheduled in the syllabus, except that it will be on zoom.

Video from review 4/23/20

slides from review 4/23/20

Lecture Recording 4/21/20

Slides 4/21/20

Lecture Recording 4/16/20

Slides 4-16-20

Lecture Recording 4/14/20

slides 4/14/20

scores to date and ESTIMATED GRADE

Hw12.7

Please note that I've assigned section 12.7 to the whole class and that is due on Saturday night at one minute to midnight.

Some things you should stop doing immediately

1) Don't include your ASU ID# in any emails to anyone.  Email is an insecure medium, and bad people could use your ASU ID# to hack your identity. (Think how embarrassed you'd feel sitting in jail doing time time for someone who pretended to be you)

2) Do you send me a copy of your ASU ID, or driver license or whatever, same reasons apply.

(FYI, I don't need that information anyway in an email.)

following the instructions...

Me:

Some people : "Bet"
 

a 12.6 problem

Hi Professor,

I am currently working on webwork right now and I am having trouble with one of the problems. The question is on converting from rectangular to cylindrical coordinates and I have plugged in all the numbers correctly so far but it keeps telling me that my theta is incorrect. I attached a screenshot of my answers with the problem and am going to move on from it for now but I was just wondering if you would be able to point out what I am doing wrong.

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Yeah, you'll have the problem with polar coordinates too. The situation is that the graph of the tangent function looks like this:

You should recall that a function is invertible only if it satisfies the horizontal line test, which this tan(x) doesn't, for example x satisfies the equation tan(x) = 1 if x = π/4, or 5π/4 or -3π/4 etc. We deal with this situation by restricting the domain of tan(x) to the range (-π/2, π/2), and then all of the values of tan^{-1}(x) are in this range too. This corresponds to (x,y) in the first and fourth quadrants. BUT <-4,1> is in the second quadrant, and this vector is exactly opposite of the vector <4,-1> that corresponds to the angle tan^{-1}(-1/4).  To get the right angle just add π to the the answer you are getting.
PS, I get the same question every semester, but it's a lot easier to explain once people have gotten frustrated trying to do it.

PPS. btw, the moral of this whole story is that you have to think about what things mean.

PPPS, if you click the "email instructor" button at the bottom of the page it will send the problem to me and you don't have to copy/paste. 

the hw

Hi professor Taylor,

I was just wondering if you are going to push the homework sections 13.1 and 13.2 back since they are due today but we have not gone over the sections yet in lecture,

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Yep, the chapter 13 hw is delayed.

lecture 4/9/20

slides 4/7/20

Video 4/7/20

Rules and requirements for the test today

1. You will need to have :

• Your laptop or desktop.
• A quiet and private space with a desk or table to take your exam.
• The zoom app installed on your platform (desktop, laptop or phone). 
• A webcam set up on your platform, or failing that your phone must have the zoom app installed.  (you should make sure that your laptop or phone is plugged in, because it would probably affect your score negatively if you ran out of power in the middle of the exam)
• Your own blank paper, about ten sheets should be more enough. 
• Your calculator. Please review the section on calculators in the syllabus, because we will inspect your calculator. 
• pencil and paper. 
• ZOOM VIRTUAL BACKGROUND MUST BE TURNED OFF.

2. The test will be administered and answers will be entered on the webwork platform. 

• You will need to have access to webwork during the exam.
• The exam will be called "test" in webwork. It will open and become visible at 4:45; you should have webwork open before this time, and reload webwork at this time. 
• MAKE SURE YOU CLICK THE "SUBMIT" BUTTON so that your answer is recorded.
• Using the "CHECK ANSWERS" button will not give you useful information. It is deliberately set up to give the wrong answer--sometimes. So feel free to use but don't trust the result. Click the SUBMIT button anyway with your answer when you are ready. 
• Make sure (if you want your scratch work to be considered in your grading, which you do) that your scratch work on paper is neatly organized and each section is labeled with the problem number, as well as clear indication of which calculation you are performing. 

3. Please be on time to class today. Your camera must be on, and your microphone on and unmuted the until you check out.  You will arrive in the zoom space in the waiting room, make sure your speakers are turned up at this time. I and the proctor will check you in one at a time: this will involve showing your id next to a view of your face, a room scan with the camera as well as showing us your scratch paper and calculator.  At this point TURN DOWN your speakers until you are ready to check out.  After you are checked in and until you have finished checking out your camera must have a view of the room.   

4. When you are finished with the exam and wish to leave the zoom meeting you need to check out with me or the TA. When and been checked out, your checkout time will be recorded in our gradebook. From this time you have TEN MINUTES to lay out your scratch work in test order, then use your phone to photograph each sheet of your scratch paper in test order and email me the photos.  I suggest your practice this ahead of time, by photographing some sheets of paper and emailing them to yourself, while a timer is running. 

5. I suggest that you review this information this afternoon before the exam starts, as it may improve and improve during the course of today. 

On the practice test, my bad

Hello Dr. Taylor, 

Im emailing regarding the practice exam question 2 part c. In lecture you gave us the answer was |<3,0,2>|, however everywhere I've looked online says to find the max rate of change using the magnitude |<18,0,12>|. Doing this I got the answer to be sqrt(463) is this correct or incorrect. I was also wondering if you could explain where you got the <3,0,2> vector. I did part b using the <18,0,12> and got the same answer however for part c it doesn't work according to the answers you gave us which was sqrt(13).Thanks and I look forward to hearing from you.

Sincerely,

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You're right, my bad.  The answer should be 4√13.