Math 341: Differential Equations (Fall 2013)
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Date Assigned Date Due Topic Hint

BONUS QUIZ 4

Fri Nov 15 Mon Nov 18

Bifurcations in Quasi-Linear Systems of ODEs

HINT: Notice that you don't have t -> infinity in part (d). Your expression for r(t) in both (c) and (d) should have an unknown constant C in it.

NOTE: the contradiction between part (a) saying the system has  acenter for all values of a when in actuality the nature of the fixed point is very different for different values of a! (i.e. Linearization doesn't work well when the Jacobian has fully complex eigenvalues or a zero eigenvalue)

QUIZ 8

Fri Nov 15 Mon Nov 18

Quiz 8

HINT #1: You basically need to do one step of integration by parts in order to get the formula for L{t^a}. Think about which function in the integral you want to differentiate in order to have t^(a-1) appear.
HINT #2: Try integration by substitution (i.e. u=st) in order to obtain the definition of Gamma[a]

READING QUIZ 3

Fri Nov 8 Fri Nov 8

Reading Quiz 3

Covering Sections 3.1, 3.2, 3.3, 3.4, 3.5 and 3.7 of Blanchard, Devaney & Hall.

BONUS QUIZ 3

Fri Nov 1 Mon Nov 4 Visualizing Systems of ODEs HINT: Also draw in the straight-line solutions. What does existence and uniqueness theorem tell you about crossing these solutions? Our general solution previously discussed applies to zero eigenvalues. What is e^0?.

QUIZ 7

Fri Nov 1 Mon Nov 4 Bifurcations in Planar Systems of ODEs HINT: What property of the matrix controls when a linear system of ODEs will change its character?

QUIZ 6

Wed Oct 23 Mon Oct 28 Planar Systems of ODEs HINT: Recall how you can check whether an eigenvector is associated with an eigenvalue is if it solves Ax=qx where q is an eigenvalue and x is eigenvector.

QUIZ 5

Fri Oct 11 Wed Oct 16 Chapter 2 Think about what pictures we have seen that represent equilibrium solutions of ODEs.

READING QUIZ 2

Wed Oct 9 Wed Oct 9 Reading Quiz 2 Covering Sections 1.5, 1.6, 1.7,1.8 and 1.9 of Blanchard, Devaney & Hall.

Quiz 4

Fri Oct 4 Mon Oct 7 First Order Linear Differential Equations HINT: Closed form means that you don't have an integral in the expression. Make sure you fill out the Reality Check to get 1 point!

Quiz 3

Fri Sep 27 Mon Sep 30 Practice with Bifurcations HINT: when sketching the bifurcation diagram, think about whether there is any value of alpha which would correspond to zero as an equilibrium value. (That tells you were your bifurcation curve crosses the parameter axis)

Quiz 2

Fri Sep 20 Wed Sep 25 Qualitative Analysis of the Logistic Equation If y'=f(y) where y is a function of t. Using the chain rule tells you that y''=f'(y)y'(t)

READING QUIZ 1

Wed Sep 18 Wed Sep 18 Reading Quiz 1 Covering Sections 1.1, 1.2, 1.3, 1.4 of Blanchard, Devaney & Hall.

BONUS Quiz 2

Mon Sep 9 Mon Sep 16 Practice with Separation of Variables What are the conditions on f(x,y) the Existence and Uniqueness Theorem that guarantee a unique solution exists?

Quiz 1

Fri Sep 6 Mon Sep 9 Introduction to Differential Equations Think about the particular solutions in u variables, what would the initial conditions be then?

BONUS Quiz 1

Fri Sep 6 Mon Sep 9 Singular Solutions A singular solution to a DE is another solution that does not fit into the family of solutions generated by changing the constant of integration.