Maple Tutor

Part 11: Symbolic solution of differential equations

In this part we explore Maple's ability to solve the logistic equation

dy/dt = y (1 - y)

and to check the solution. Then we will adapt the solution procedure to an initial value problem with this same differential equation. In the next part, we will relate these algebraic calculations to the geometry of direction fields.

1. Give the differential equation a name by entering
DE1 := diff(y(t), t) = y(t)*(1 - y(t));
Then ask Maple to solve the equation for y by entering
dsolve(DE1, y(t));
Note that Maple uses _C1 to represent an arbitrary constant.

2. Differentiate your solution expression with respect to t to get an explicit expression for dy/dt. Then use your solution expression to find an explicit formula in t for y(1 - y). Is this formula the same as the one for dy/dt? You may want to simplify the output before you try to answer this.

3. Now we add the initial condition y(0) = 0.1 to determine a single solution of the differential equation. To tell Maple to solve the intial value problem, put the two parts of the problem -- the differential equation and the initial condition -- in a list:
dsolve ( { DE1, y(0) = 1/10 }, y(t) );

4. What do you have to do to check the answer from the preceding step? Have you done it already? If not, can you get the checking technique from what you did in Step 2?

5. Before you move on to the next part, define a function h(t) to be the solution of the initial value problem in Step 3. We will use this function in the next part.