Dear Mah251(22,23,24) students

1. First FAQ:

 (i) Except for the last question in 14.1 (#37) all the problems in that section are MANDATORY
    BUT, you are welcome to use Maple's plot3d command, and they figure out the slices by looking at it.

 For example 14.1 #23

 plot3d(x^2+4*y^2, x=-4..4,y=-4..4);

(ii) To get the curvature of a PLANE curve r(t)=<x(t),y(t)>  you can use the formula for a SPACE curve and use r(t)=<x(t),y(t),0>

(iii) The book's answer to 13.4 #21 is CORRECT. Note that this tedious question uses  hyperbolic-trig functions.
    Note also that  1/cosh(t) IS sech(t) (Like 1/cos(t) is called sec(t)). It is confusing, since the first letter of cos (and cosh) is c
but the first letter of their reciprocal is s

(iv) A particle that moves according to r(t), is SPEEDING UP at time t=t0, if the dot product v(t0).a(t0) (alias r'(t0).r''(t0) 
is POSITIVE, if is SLOWING DOWN if it is NEGATIVE, and it is NEITHER if it is 0.

2. Thanks for most of you who submitted, in  a timely manner the homework. Reminding you that it is not graded
carefully, but INSPECTED, and the homework grade will be determined at the end of the semester.

BUT it is MANDATORY to submit a .pdf (or .txt) file called (e.g. of the next homework assignment)

FirstLastOct4.pdf (or if you wish FirstLastOct4.txt) with EXACTLY this naming convention (NO .jpeg NO .png or other formats are allowed)

It is also MANDATORY, after each lecture to submit TWO kinds of attendance quizzes, that you should download
from

https://sites.math.rutgers.edu/~zeilberg/math251_20.html

and rename them EXACTLY as requested, or else my computer will not recognize them. For example for Lecture 7

q7DoronZeilberger.pdf ( a .pdf file)

AND

aq7DoronZeilberger.txt ( a .txt file)

PLEASE no .rtf and use EXACTLY this convention.

3. Unfortunaley, I have neither TA nor grader, and I don't have time to "police" you and write you emails that
are you tardy. If you need an extension, then email me. It is better to submit empty (or incomplete) homework
and empty attendance quizzes than nothing at all.

But if you can't afford the time to submit these 5 files EVERY week (the homework .pdf due each Sunday night)
and the TWO attendance quizzes for EACH lecture (due after each lecture)  then you should this class, since
I won't even look at your midterms and final.

4. Soon I will post a SAMPLE midterm exam but not on this current material, but rather on topics from calc1 and calc2.
Just to make sure that you will get used to this strange way of submitting examps via email that MUST
be .txt file

5. I hope to soon post a Maple workshop that is also mandatory, but you will have a week to complete it.

6. While attending live recitations is optional (after all this class is AR) it is encouraged, and it also
helps me, to get feedback.

7. If you have any questions, feel free to email me.

8. I really apperciate the good efforts of the majority of the students. Those few who did not email their
homework and/or quizzes please start doing it asap. These are hard times, and I HATE to fail anyone.

 Best wishes
   Dr. Z.