Comments on the Assignment 3.

Problem 1.3.8
Was worth five points.
The average score was: 4.88
*Comments:
I think the book was looking for
something along these lines:
2x - 3 < 3x - 2
iff -3 < x -2
iff -1 < x

4x - 1 < 2x + 3
iff 2x - 1 < 3
iff 2x < 4
iff x < 2

Therefore -1 < x < 2.
Therefore the solution set is: (-1, 2).

The solution set for
2x - 3 < 3x - 2 is: (-1, +infinity).

The solution set for
4x - 1 < 2x + 3 is: (-infinity, 2)

(-infinity, 2) Intersected (-1, +infinity) = (-1, 2). done.

Full credit was given if the student just found that the
soln set was (-1, 2).


Problem 1.4.6
Was worth five points.
The average score was: 4.81

Problem 2.1.6
Was worth ten points.
The average score was: 8.50
*Comments:
-8.5 points were given for correctly finding
a value of delta (w/ work and reasoning shown).
-1.5 points were given for drawing a graph.
-One point was deducted for not mentioning that
f(x) is an increasing function and how that
constrains the range of f(x).

Problem 2.3.6
Was worth ten points.
The average score was: 5.77
*Comments:
-At least eight students thought that
if f(x) was defined at 'a', then
f(x) was continuous at 'a'.
-Most students were able to prove that
(x^2 - 27)/(x^2 +2x + 1) is continuous at 3,
but many stopped there without invoking
theorem 2.10 or theorem 2.5.

The average score for Assignment 3 was:
23.96/30.