Question:
Consider the differential equation dy/dx = x + 2.
Answer:
To compute the value of the derivative at x = 1, substitute x = 1 into the differential equation dy/dx = x + 2:
dy/dx = x + 2 dy/dx = 1 + 2 dy/dx = 3
Therefore, the value of the derivative at x = 1 is 3.
To sketch the slope field, we plot small line segments at various points on the x-y plane based on the slope at those points. The slope at each point (x, y) is given by x + 2.
The following slope field is obtained:
To estimate the solution to the differential equation that satisfies the initial condition y(0) = -1, we use the slope field. Starting from the point (0, -1), we follow the slope field lines to sketch the approximate solution curve.
Starting from (0, -1), at x = 0, the slope is 2. We move upward by 2 units to reach the next point. At x = 1, the slope is 3. We move upward by 3 units to reach the next point. Continuing this process, we sketch the approximate solution curve as follows:
Based on the slope field, the approximate solution to the differential equation that satisfies the initial condition y(0) = -1 is shown by the curve above.
To find the exact solution to the differential equation with the given initial condition, we need to integrate both sides of the equation.
dy/dx = x + 2
∫dy = ∫(x + 2)dx
Integrating both sides, we get:
y = (1/2)x^2 + 2x + C
Now, using the initial condition y(0) = -1, we can solve for the constant C:
-1 = (1/2)(0)^2 + 2(0) + C -1 = C
Therefore, the exact solution to the differential equation with the initial condition y(0) = -1 is:
y = (1/2)x^2 + 2x - 1