Let
y coskt
a
Find the values of k such that y satisfies the differential equation
yy
Enter your answers as a commaseparated list.
k
b
For the values of k found in part a show that every member of the family of functions
y A sinkt B coskt
is also a solution of the differential equation.
We begin by calculating the following.
y A sinkt B coskt y Ak coskt Bk sinkt y
Note that the given differential equation
yy
is equivalent to
yy
Now, substituting the expressions for y and
y
above and simplifying, we have
LHS yy
A sinkt B coskt
Bk cosktA sinktB cosktk
k B coskt
since for all value of k found above,
k