final scores

review question

I was wondering if you could please walk me through this problem because I cant quite seem to understand how to get it. for #4 in the 13.5 section of the final review it says let bold r= xi+yj+zk and r= I (bold r) I. then find del dot product (9 r boldr). the answer is 36r but I don't know how to get that. If you could find time to help me out id greatly appreciate it. Thank you and happy cinco de mayo haha

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So...r= xi+yj+zk is the vector and r=√(x^2+y^2+z^2) (what the textbook calls ρ-notice I didn't write this problem so I'm not the only one who prefers r to rho is three dimensions).  So we get a new vector field rxi+ryj+rzk, and

(rxi+ryj+rzk)=∂(rx)/∂x+∂(ry)/∂y+∂(rz)/∂z=(x∂r/∂x+y∂r/∂y+z∂r/∂z)+r(∂x/∂x+∂y/∂y+∂z/∂z

(by the product rule)                                        =(x∂r/∂x+y∂r/∂y+z∂r/∂z)+3rNow, ∂r/∂x=x/r, ∂r/∂y=y/r and ∂r/∂z=z/r, so (x∂r/∂x+y∂r/∂y+z∂r/∂z)= (x^2+y^2+z^2)/r=r,(rxi+ryj+rzk)=4r and so (9rr)=9x4r=36r. 

Estimated Grades as of Friday 5/2/14

odds & ends (Important!)

1) The webwork for section 13.7 is open now and is due on Sunday at 11:59am.

2) The extra credit essay is worth 1.5% of your grade

3) The final exam is next Tuesday from 7:10 - 9:00 PM 

4) There is a mat267 review session run by the student success center this Sunday May 4 5:30-6:30pm is PSH 150.

New Comment on extra credit

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[Tom Taylor's MAT267 Blog] New comment on Extra Credit assignment.

When and how would you like this turned in to you? 

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At the final exam

Coverage of the Final Exam

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The final exam will be comprehensive; however the sections covered after midterm 3 will receive somewhat more detailed emphasis.

Attendance as of 4/25/14

Note that a majority of the people left in the class have missed at most two days of class.

Extra Credit assignment

A five page paper, single-spaced, with inline citations and references, describing just how multivariable calculus relates to your chosen discipline.  NO PLAGIARISM. All material copied verbatim from another source must be attributed and in quotes.  IF I CAN DO A GOOGLE SEARCH ON ANY FIVE WORD STRING FROM YOUR PAPER AND GET THE SAME PARAGRAPH, you don't want to know what will happen.

Final Exam Reviews

Are here.

By the way...I shouldn't have to say this, but the final exam date and time are as stated on the syllabus.

Homework next week

Webwork section 13.5 and section 13.6, due Wednesday April 30@8:00am

ASU School of mathematics & statistics mat276 review & review session

Here. It may be helpful if you tried to work these problems before you attend the review session tonight (see below).

Disclaimer: I did not make this review (in fact I learned about the review from your classmates). While the problems in this review are related to the course material that may be covered on the exam, they should not be taken as a representing any specific problem(s) that appear on the actual exam.  In addition, your exam may also contain material from section 12.3, which is not covered in this review.

The exam will cover...

Sections 12.3-13.3

Course Evaluations

This is your chance to grade your instructor: you can access the Course Evaluation participant portal on MyASU through the 'Course Evaluations' link under under 'My Classes.'

Wake up call

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Dr. Taylor,

In the MAT 267 webwork assignment 13.1, question 7, I am unable to view the
images in the problem due to my "security settings". I tried opening up the
question with both Chrome and Firefox, since it does not tell me what
security settings I specifically need to change to fix the problem, but
this did not solve the problem. If you could get back to me on what you
think I should do about this, that would be fantastic.
Thanks,

*************

Please read *ALL* of this post.  As far as the rest, you should try Explorer or Safari depending on your platform

Small detail on the homework

I opened section 12.3 and 12.4 because I understand that some people want to see the problem, but they aren't due until next monday and next wednesday respectively.  Remember that I recommend that you NOT spend all of your time working on these problems, but rather spend your time STUDYING for the exam.

Test 3 Reviews

Hello,

Below is the information for the Test 3 Reviews for your course:

MAT 267:

4/15                       6:00 pm                Hayden L-62

4/16                       6:00 pm                Hayden L-62

\Please inform your students

Webwork questions 4/13/14

Why would x*i be wrong?

and

I have only attempted this problem twice, but I'm not really sure how to
even go about solving a problem like this. If you could please explain and
expand that would help. Thank you.

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Well for one thing, i is parallel to the x-axis and you need something parallel to the y-axis.

Edit: it looks like I need to be a little more clear with this.

First of all, two dimensional vector fields look like

;

for every (x,y), P(x,y), and Q(x,y) are both numbers, the x-component of V is P and the y-component is Q.  The direction of the vector field at a point depends on the relative size of P and Q, which have all vectors parallel to an axis would have one of the components equal to zero.  On the other hand, if
 i.e. if P(x,y)=P(x) and Q(x,y)=Q(x),  (or respectively if  , i.e. if P(x,y)=P(y) and Q(x,y)=Q(y)) thenwill be independent of y, respectively will be independent of x. 

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For those with java problems with their webwork: please follow the instructions below.
Caveat & Disclaimer: the Java security exceptions are there because there is a real security risk due to persistent security loopholes in the Java platform.  You are responsible for maintaining the security of your own machine, not the university.  When you are done using Java for this problem, you may wish to reverse the process and disable Java.


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Dear MAT 267 instructors,

the latest versions of Java have increased security settings that will prevent execution of the applet that creates interactive 3d figures in some of our webwork sets (such as MAT 267).  To fix it, 

Go to the Java Control Panel (on Windows click Start and then Configure Java)
Click on the Security tab
Click on the Edit Site List Button
Click the Add in the Exception Site List window and enter
https://webwork2.asu.edu
Click Add again and enter
https://webwork.asu.edu

You might want to send these instructions to all the students.

webwork for next week

Section 13.1 is now open and is due Tuesday April 15 at 5pm.
Section 13.2 is now open and is due Thursday April 17 at 5pm.
Section 13.3 will open on Wednesday April 16 and is due Monday April 21 at 8:00am

Another Webwork Question

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For problem 13 on 12.7, Webwork does not like my phi limits. The problem
says the angle at the vertex is "pi/3" so wouldn't the limits be from pi/3
to 0? Having a hard time understand why this isn't the case.

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First of all, I don't think that that the statement of this problem very clearly specifies which angle is π/3 at the vertex, and yes I think it would be reasonable to assume that the angle they meant was the angle from the z-axis to the cone and this would indeed mean that the limits of integration in φ was from 0 to π/3.  However, it seems that the angle they mean is either the angle from the x-axis to the cone in the x-z plane or the angle from the one side of the cone to to the other in the x-z plane, which would make the  φ integration from 0 to π/6.

Webwork Due Date

Hi All, due to the recent network security glitch, the section 12.7 webwork, which was due today at 2pm, is now due tomorrow at 8:00am

Webwork question

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***** The feedback message: *****

This is the problem I am having trouble on, it keeps saying that it doesn't
look like an implicit equation. I'm not exactly sure what that means so if
you could please help clarify exactly what this problem is looking for I
would greatly appreciate it.

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There's nothing wrong with what you did, except that it asked for an equation in polar coordinates and you gave it the solution of the equation in polar coordinates.  Webwork would have approved of your answers if you had stopped about two steps back in inputed the whole equation you had then.

HW due next week

It seems to have worked well for the webwork due dates to be more evenly spread through the week, so let's do it again.

Webwork section 12.6 due Tuesday April 8 at 2:00pm
Webwork section 12.7 due Thursday April 10 at 2:00pm
Webwork section 12.8 due Friday April 11 at 8:00am

Webwork question

This  message was automatically generated by the WeBWorK system at
https://webwork2.asu.edu/webwork2/, in response to a request from
*************

Click this link to see the page from which the user sent feedback:
https://webwork2.asu.edu/webwork2/Taylor_MAT_267_Spring_2014/?effectiveUser=*****

***** The feedback message: *****

I don't quite understand what this problem is asking us to take the limit
of.  After (polar) integration, my resulting expression is the sum of two
trigonometric functions, with psi as their argument, a constant term, and a
term that is the product of c and psi.  I'm not sure how to go about taking

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First of all, a point of information and a request.  I am getting webwork questions from you guys without mention or identification of the question in discussion.  I'm not sure if this is a webwork problem or because you guys are not sending feedback from the question itself.  Please make sure that your webwork questions originate from the specific problem *AND* that your feedback mentions the webwork question number.  Otherwise I may not have time to search through all of the problems to answer your question.  Now, I guess that you are referring to the this webwork problem:

The situation is that your relative has baked a lopsided cake and you would like to slice it in half so that each half has an equal volume of cake. If c=10 the cake is very lopsided: the cake comes to a thin edge at one point and a thick edge at the opposite side.

On the other hand, when the c=30 the cake is relatively more even.

When c is small, given that your first cut is along the positive x-axis and that the peak of the cake is somewhere between the positive x-axis and the positive y-axis you will need to choose your second cut somewhere between before the negative x axis in order to split the cake fairly.   As c--> infinity, I guess that the position of the cut will tend to the negative x axis--but this is what you have to prove.

Homework Due Next Week....(nothing gets done except for the last moment)

You have a lot of homework to do for next week....from which I get the picture of desperate students desperately trying to finish their webwork all night on Thursday night....and not being happy with their success.  Accordingly, let's motivate you to spread this out a little bit by making half the homework due next Tuesday, and the other half due on Friday.

Webwork section 12.2 and section 12.3 due Tuesday April 1 at 2pm.
Webwork section 12.4 and section 12.5 due Friday April 4 at 8:00am

The Exam....

Will cover all of chapter 11 and sections 12.1 and 12.2.

Test 2 Review Session & Pretest office hours.

There will be review sessions for Test 2 on 3/18/2014 and 3/19/2014, 6-7PM in Hayden L62.

I will have pretest office hours Noon-1PM on Tuesday and Thursday, and 2-3PM on Wednesday.

Test 2 Review Document

Homework Due 3/18/14

Webwork section 11.7 and section 12.1

Webwork Question

Professor Taylor,
For this hill-climbing problem I have tried computing the gradient and
making it into a positive unit vector, but I keep getting the wrong answer.
How do I do this problem?

Thanks,
#######

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Since you don't specify, I guess you mean a problem like this one.18:

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The direction of maximal increase is in the direction of the gradient.  Since grad(z)=-0.18i-0.08j, the unit vector in this direction is u=grad(z)/|grad(z)|=(-0.18i-0.08j)/√(0.18^2+0.08^2)=-0.914i-0.406j.  The angle above the horizon can be obtained from the dot product of u with a ±i.

Most Recent Scores as of 3/5/14 & estimated grade

These are the most recent homework, quiz and exam scores as of 3/5/14.  Also included is an estimated current course grade--this is an estimated grade only, since course policy says that the grade is to be based on 50% midterms, 25% final, 15% webwork and 10% quizzes.  Since you haven't taken the final yet, I am instead estimating the grade as 75% midterm, 15% webwork and 10% quizzes.

Attendence to date

homework error question

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12:03 PM (8 hours ago)

Is my work off? Because I keep getting it wrong

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You've done everything correctly except for the fact that 168-9-55=104.

Homework Due 3/7/2014 at 8:00am

Webwork section 11.4, section 11.5 and section 11.6.

webwork questions & more webwork questions

How would you use polar coordinates to solve this?


***** Data about the user: *****

Status:     Enrolled ('C')
Section:    10983
Recitation:
Comment:

***** Data about the problem: *****

Problem ID:                   6
Value:                        1
Max attempts                  unlimited
Random seed:                  2513
Status:                       0.5
Attempted:                    yes
Last answer:
        AnSwEr0001: dne
        AnSwEr0002: 5
Number of correct attempts:   0
Number of incorrect attempts: 10
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A. lim(x,y)→(0,0)(x+12y)2x2+144y2= ___

B. lim(x,y)→(0,0)5x3+10y3x2+y2= ___

(Hint for B: use polar coordinates, that is x=rcos(θ),y=rsin(θ) )
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well,  I would substitute in the numerator and denominator the suggested coordinate transformation, and take advantage of the fact that the denominator takes an especially simple form, since x^2+y^2=r^2cos^2(θ)+r^2sin^2(θ) =r^2(cos^2(θ)+sin^2(θ))=r^2, and also of the fact that r->0 as (x,y)->(0,0).

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How do I find an integer for this problem?
Problem ID:                   6
Source file:                  Local/Dartmouth/setStewartCh15S3/problem_6.pg
Value:                        1
Max attempts                  unlimited
Random seed:                  3762
Status:                       0.75
Attempted:                    yes

Number of incorrect attempts: 12
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The gas law for a fixed mass of an ideal gas at absolute temperature T, pressure P, and volume V is PV= mRT, where R  is the gas constant. Find the partial derivatives

∂P∂V=____

∂V∂T=____


∂T∂P=____


∂P∂V∂V∂T∂T∂P================   =
=______ (an integer) 
∂P∂V∂V∂T∂T∂P=         
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Well, it looks like you correctly computed the individual partial derivatives, so all you need to do is to multiply them together, and then maybe to substitute the ideal gas law back into the product so you can cancel everything except an integer constant
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I got the answer for most parts, but don't understand why the lim along the
y-axis is 0. I am not sure how to get the lim along the line. I have
guessed multiple times, but am unsure what to do with the constant.

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Well, x=0 on the y-axis, so the value of the numerator is 0 while the value of the denominator is 5y^2; in other words the value of the function on the y-axis is 0 except at the origin, where it is undefined. Since the limit of zero is zero, we're done.