### Dr. Sarah's Comments and Peer Review for Amanda and Katie C's Number 9

### Dr. Sarah's Comments

Notice that there are MANY equilibria for the last part.
(Play around with the graph by changing x= ..
to different numbers). Here are JUST SOME of the
equilibria.
Need separate fsolve commands at the end:
f1:=fsolve((0.1*y)-sin(y)=0,y=-4..-2);
f1 := -2.852341894
is unstable

f1:=fsolve((0.1*y)-sin(y)=0,y=-1..1);
f1 := 0
is stable

f1:=fsolve((0.1*y)-sin(y)=0,y=2..4);
f1 := 2.852341894
is unstable

f1:=fsolve((0.1*y)-sin(y)=0,y=4..8);
f1 := 7.068174358
is stable.

### Peer Review

Needed to define stable/unstable a little better, otherwise fine

Interesting graph, need to describe stable and unstable on Maple
text.

Good job, but I don't totally understand this stuff

I could follow this pretty well... It was good!

Tough assignment - presentations get harder as those who have
already gone have time to relax and ask questions and confuse presenters.

Good explanation of graphs of problem - good job! Just a question
(no reflection on them) but what is a stable equilibrium point
or line?

They did a good job.

Nice and neat worksheet, good presentation

They seem to know what they are talking about

Stable? (defined in talk), good explanation of graphs

Good job! That looked like a TOUGH problem!

Good explanation of stable points on graph, good comments on worksheet.

Interesting problem which was clearly stated, good estimates, good question
and answer.

Good exploration, good maple work, interesting

helped me understand stable points

great job, liked your preparedness and the way you answered questions

good presentation. they handled it very well and seemed to have
a good grasph of the concepts which they were trying to investigate

great explanation of stable and unstable equilibrium points

They seemed to have a fairly good grasp on the concepts of
the directionfield plots and had good text comments.

looked very precise