Re: Integrals In Spherical Coordinates

grubb_at_math.niu.edu
Date: 12/07/04 

Date: 7 Dec 2004 09:28:23 -0800

meyousikmann wrote:
> "Daniel Grubb" <grubb@lola.math.niu.edu> wrote in message
> news:cnt3u3$hgk$1@news.math.niu.edu...

> > First of all, you should go back and do some algebra. I suspect
that
> > you solved for z by going from z^2=9-x^2-y^2 and taking square
roots
> > to get z=3-x-y. If that is the case, I would almost immediately
give
> > you 0 points for this problem. Nobody in third semester claculus
> > should do this mistake *ever*.
> >
>
> Well, let me first say thanks for the pointers....they are truly
> appreciated. Second, may I also say that I am glad I do not have you
for an
> instructor. I realized my mistake after walking away from the
problem and
> coming back with a "fresh" perspective. Don't you think zero points
is a
> little harsh? That is typically why students fear math and science
> courses....no room for error. We learn from mistakes. You scare us
away
> with zero points. How about a bit of encouragement to keep plugging
instead
> of a blanket statement that makes the student want to quit. It is
called
> learning.

Of course there is a progression. I would not give a 0 for this in calc
I.
I *would* take off a significant number of points though. By the third
semester of calculus, the thought that 'everything is linear' should be
long gone. That it isn't is a sign of some deeper problems in
understanding
that should have been addressed *years* before. I do leave 'room for
error'
when teaching third semester calculus, but the errors should be from
the
first two semesters and non-trivial rather than in *basic* algebra. If
someone tends to make this type of error, they simply are not ready for
that class and should go back and tend to the pre-requisites.
Sorry if I'm the deliverer of bad news.

--Dan Grubb

Quantcast