In this problem y c1 cos 3x c2 sin 3x is a twoparameter fa
     In this problem, y = c_1 cos 3x + c_2 sin 3x is a two-parameter family of solutions of the second-order DE y\" + 9y = 0. If possible, find a solution of the differential equation that satisfies the given side conditions. The conditions specified at two different points are called boundary conditions. (If not possible, enter NOT.)  y(0) = 0, y\'(pi/6) = 0  y =   
  
  Solution
y\"+9y=0
Auxiliary eq=0
is D^2+9=0
(D+3i)(D-3i)=0
D=3I,-3i
Solution is y(x)=c1 cos3x+c2sin3x
y\'(x)=-c1sinx+c2cosx
y\'(0)=c2=0
y\'(pi/6)=-c1(1/2)=0
Implies that c2=0
Hence y=0 (0sin3x+0cos3x)

