Since y''' = 0, when we integrate once we get:
y'' = A (A is a constant)
Integrating again gives:
y' = Ax + B (A, B are constants)
Once more:
`y = (Ax^2)/2 + Bx + C` (A, B and C are constants)
The boundary conditions are:
y(0) = 3, y'(1) = 4, y''(2) = 6
We need to substitute these values into our expressions for y'' and y' and our general solution, `y = (Ax^2)/2 + Bx + C`.
Now
y(0) = 3 gives C = 3.
and
y''(2) = 6 gives A = 6
(Actually, y'' = 6 for any value of x in this problem since there is no x term)
Finally,
y'(1) = 4 gives B = -2.
So the particular solution for this question is:
y = 3x2 − 2x + 3
Checking the solution by differentiating and substituting initial conditions:
y' = 6x − 2
y'(1) = 6(1) − 2 = 4
y'' = 6
y''' = 0
Our solution is correct.