Partial Derivatives and Graphing Functions

Solve the following questions. Show all steps and reasoning for for questions 22 and 28.

  • So you only need problems 22-28?

  • I need all of the questions answered, but only need explanations and reasoning for questions 22 and 28.

  • Well, that's too many questions for $115, but I'll answer as I have already accepted. Thanks.

  • I'll tip after to make up for it. Thank you.

  • I saw your post about your quiz a few days ago. A better way to arrange for your quiz is to communicated with users who have previously answered your question by commenting on your previous questions. Let them know when you are going to post the quiz and ask them to be online at that time. If your deadline is shorter than an hour, you may also set your deadline in the body of the question, simply by stating it.

  • I might be able to help if you let me know when you will have the next quiz.

  • Hey Philip. Thanks for your response. I have 4 online quizzes that I need to finish in the next few days. Each quiz is 20 true or false questions with a 20 minute time limit. If you're willing to go over at least one or two of them, just let me know the day and time (with time zone) and I can confirm here and post them then. Also let me know how much you would like for the help. Cheers.

  • A few things were missing or showed as wrong for this assignment: 1 was wrong, but I was able to find that the half disc radius was 4, not 16. For 11, when are both fx and fy continuous functions (for xy>___)? The answer for 12 where you use the approximation to find an answer was wrong. 17 showed as wrong. For 22, I had trouble reading the saddle point. Is the saddle point is (0,0,1) for (x,y,f)? 28 also showed as incorrect. If you could double check these it would be appreciated.

  • See the body of the answer for 11,12, and 22. I will upload corrected solutions for 17 and 28 as an attachment.

  • I can help you with your quiz tomorrow morning anytime before 2 PM (PDT, California time). I would charge $40 per quiz.

  • Thanks Philip. If you're free at 11am PDT tomorrow, we could go through at least a couple of them, and depending on how you feel we might be able to get through them all. I'll comment here a little before 11am to make sure you're ready, and if we continue with more I'll comment on the most recent post accordingly to ensure we're both ready and good to continue.

  • Sure. Can we do it earlier? If not 11Am is fine.

  • Yeah, we can start at 9am or 10am if you'd prefer.

  • 9Am is great. I'll be online, but comment here before you post to make sure that I am online.

  • No problem, see you then!

  • I am online. Are you going to post in 15 minutes? I will submit solutions for the first 5, the second 5, and so on so you can review them while I am working on other ones.

  • Perfect, that makes sense. I'll post in 10 minutes, which should be exactly 9am PDT.

  • Cool. I would have a total of 20 minutes?

  • So this first quiz actually only has 10 questions and you have 16 minutes. Just posted it.

Answer

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2 Attachments

  • See the second file for questions 17 and 28. Let me know if you have any other questions, and sorry for the mistakes. There were computational mistakes.

  • Please note that I spent several hours to answer this post. I would say the offered bounty was very low for my rate.

  • For question 22, the saddle point showed as incorrect. I believe this is because it is meant to have a third point, for the form (x, y, f). Could you please check this again? Sorry for the inconvenience. Once the answer is accepted I'll tip to make up for the low bounty.

  • Oh ok. The saddle point must be then (0,0,0).

The answer is accepted.