Hence the equilibria (1,1) and (-1,1)
At equilibrium point (1,1),
Since alpha =1 is greater than 0, the solution is unstable , repelling spiral point.
At equilibrium point (-1,1),
Since the eigenvalues are real distinct roots
A Power Primer
New York University
One possible reason for the continued neglect of statistical power analysis in research in the
behavioral sciences is the inaccessibility of or difculty with the standard material, A convenienti
Journal on Quality and Safety
Human Factors Engineering Series
Human Factors Risk Management
as a Way to Improve Medical
A Case Study of the Therac 25
Radiation Therapy System
Case Study. Ray Cox of Tyler, Texas, was schedu
Consider the Lorenz system below which models "certain modes" of the atmosphere (x, y, and z
are related to pressure, temperature, and humidity)
dx/dt = -10x + 10y,
dy/dt = 25x - y - x z, dz/dt = x y -3 z
Find the equilibria.
Produce a phase-space p
Since , the general solution is equal to
f) means trajectories are closed loops. See p. 347 of the text of how to Figure
6.3.3 and Example 4 to draw the phase-plane.
a) (Final Fall 1998 Problem 7) For each of the following answer
y 6 y + 13 y = 0
solutionA:y = e3 x sin ( 1 x )
Since alpha = 0 (i.e. the eigenvalue is purely imaginary), the solution is a center and is
Since the eigenvalues are real distinct roots, with one eigenvalue positive and the other
eigenvalue negative, the solution is unstable.
1. A tank contains 10,000 liters of a solution consisting of 100 kg of salt dissolved in water.
Pure rocky mountain spring water is pumped into the tank at the rate of 10 liters/second.
(The mixture is kept uniform by stirring.) The mixture is pumped out
1. (Final Spring 1996 Problem 2) Find the general solution of the following differential
a) Integrating Factor Method:
b) First find the homogeneous solution and then find the particular solution to find
the general soluti