Solve the following differential equation with the given bou
Solve the following differential equation with the given boundary conditions.
- If there are infinitely many solutions, use c for any undetermined constants. -
If there are no solutions, write No Solution.
- Write answers as functions of x (i.e. y=y(x)).
y+9y=0
A) Boundary conditions:
y(0)=1
y(/3)=1
y=--------------------------------
B)Boundary conditions:
y(0)=-1
y(19/6)=1
y=-------------------------------------
C)Boundary conditions:
y(0)=1
y(/3)=1
y=-----------------------------------------
Solution
y+9y=0
First solve this De and find general solution
Aux equation is m^2+9 =0
m = 3i , -3i
Hence solution is y = A cos 3x + B sin 3x
------------------------------------------------------------
a) Boundary conditions:
y(0)=1
y(/3)=1
-1 = A and 1 = 1+0
Hence B can be artbitrary
y(x) = -1 cos 3x + B sin 3x
--------------------------------------------
b)
y(0)=-1
y(19/6)=1
Substitute to get
-1 = A
and 1 = A cos 19pi/2 + B sin 19pi/2
i.e. 1 = -1(0) + B(-1)
B = -1
Hence y(x) = -cos 3x - sin 3x
-------------------------------
c) y(0)=1
y(/3)=1
-1 = A and
-1 = -1 cos pi + 0
Hence no solution for A and B

