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Section D.1 Section 3.2

Exercises Exercises

1.

Check if the following functions are solutions to the given EQ.

  1. Check directly if y1=2e5t is a solution or not to y′′−6y′+5y=0.
  2. Check directly if y2=2et is a solution or not to y′′−6y′+5y=t.
2.

Recall that if y(t)=ert is a solution to the ODE given by

ay′′+by′+cy=0

for constant a,b,c where a≠0, then the exponent r in front the t must be a solution to the characteristic equation ar2+br+c=0.

By yourself, rederive that if y(t)=Aert is a solution to the equation above, then the number r must satisfy the characteristic equation ar2+br+c=0 or A=0.

3.

Use the method given in Section 3.2 to find the general solution to

y′′+5y′−6y=0
4.

Use the method given in Section 3.2 to find the general solution to

y′′−7y′=0
5.

Use the method given in Section 3.2 to find the particular solution to the IVP

y′′+y′−20y=0,y(0)=18,y′(0)=9