Friday, February 5 Announcements

Friday, February 5
WeBWorK #5 is now open
Due Wednesday, February 10 at 9pm
Covers material from “Week 5”—see syllabus online
Quiz #2 solutions online; papers in Math Learning Centre
Quiz grades:
Our section’s average 4.7/10. An improvement, but still
lower than we want!
Essential to master: FTC1 problems with Chain Rule (like
#1), and substitutions in definite integrals (like #2).
Term marks scaled, so if we do well on the final, scores will
come up. Just make sure we know our stuff!
If you think yours wasn’t graded right: check online
marking scheme first. Then hand me official “regrade form”
(quizzes web page) with your quiz paper, by next Friday.
Friday, February 5
Clicker Questions
Clicker Question 1
Some quadratic polynomials
can be factored into two linear
polynomials with real numbers
as coefficients:
A. when c ≥ 0
B. when b2 − 4ac ≥ 0
C. when 2ax + b ≥ 0
D. always
3x2 + 7x − 6 = (x + 3)(3x − 2)
x2 − 5 = (x + 5)(x − 5)
E. when two of the numbers
a, b, c have different signs
In general:
The reason:
When does the quadratic
polynomial ax2 + bx + c factor
into two linear polynomials in
this way?
ax2 + bx + c factors this way
⇐⇒ it
√has one or two roots
⇐⇒ b2 − 4ac is defined (by
the quadratic formula)