### Homework (Recommended Problems)

Here are the recommended Homework problems for the

- Ninth edition (current edition)
- Eighth edition

These exercises are not to be handed in for marking. Instead, you are encouraged to work on these selected exercises as part of your studying for the course.

### Assignments

Assignment due dates will be posted on the Announcements page once they have been given in class. Any extra hardcopies of the current assignment will be in the bin outside my office.

### Homework Hints

Section 26.2:

- Question 9: Here's the graph
for y=x
^{-2}. - Question 17: Here's the graph for y = x - 2*sqrt(x).
- Question 27: Here's the graph for the intersection of these curves. The area they want is the roughly triangular shape to the left of the parabola. (If I asked this question, I'd definitely give the graph!)

Section 26.6:

- Question 37: Think of the cone as the surface of revolution created by whirling a straight line about the
*x*-axis.

Section 28.4:

- Question 21: This one's kind of annoying. I'd suggest that you change all of the tangents to sines and cosines, then simplify the resulting complex fraction. You should be able to use the double-angle identities once that's done. (Nitpicker from hell note: there's actually a two-step method for this one if you use a trig identity that I do not include on your formula sheet.)
- Question 23: Hint: multiply numerator and denominator each by (1 - cos x) and simplify.

Section 28.10

- Section 28.10: Gilles' Solution to Question #19 (#20 in the 8th edition) – not for the faint of heart – only try if you want a challenge!

### Textbook Errors

Ninth edition

- Section 28.2: There is an error in the answers in the back of the text to
Section 28.2, #37. The correct answer should be y=ln(3.5/(3+cos x)) + 2 --
in other words, the 2 should be
*outside*the ln brackets, not inside. - Section 28.6, question 29: the
*x*^{3}in the numerator should be*x*^{2}(squared instead of cubed) instead.

Eighth edition

- There is an error in the Student Solutions Manual. The answer
for Section 28.8 - #5 in the back of the book is correct, but in the
solutions manual, you'll note that if x = tan θ, then dx
cannot be sec θ tan θ dθ -- it must be sec
^{2}θ dθ instead. - There is an error in the answers in the back of the text to
Section 28.2, #37. The correct answer should be y=ln(3.5/(3+cos x)) + 2 --
in other words, the 2 should be
*outside*the ln brackets, not inside.