All Flashcards
How do you find the radius of convergence of a power series?
- Apply the Ratio Test. 2. Solve the inequality L < 1 for |x - r|. 3. The radius of convergence, R, is the value such that |x - r| < R.
How do you determine the interval of convergence of a power series?
- Find the radius of convergence, R. 2. Test the endpoints x = r - R and x = r + R in the original series. 3. Determine whether each endpoint converges or diverges. 4. Write the interval of convergence using appropriate brackets.
What is the first step in finding the interval of convergence for ?
Apply the Ratio Test to the series.
After applying the Ratio Test, how do you find the radius of convergence?
Set the limit L < 1 and solve for |x - r|. The value on the right side of the inequality is the radius of convergence.
After finding the radius of convergence, what's the next step to find the interval of convergence?
Test the endpoints of the interval by plugging them back into the original series and determining if they converge or diverge.
How do you test the endpoints of the interval of convergence?
Substitute each endpoint value into the original power series. Then, analyze the resulting series using convergence tests (e.g., alternating series test, p-series test).
Define a power series.
A series of the form , where n is a non-negative integer, is a sequence of real numbers, and r is a real number.
What is the radius of convergence?
The radius of convergence defines the interval around the center of a power series where the series converges.
Define the interval of convergence.
The interval of convergence is the set of all x-values for which a power series converges. It may include or exclude the endpoints.
What does 'centered at x = r' mean for a power series?
It means the power series is expressed in terms of (x - r), where 'r' is the center of the interval of convergence.
What does the Ratio Test tell you about the convergence of a series?
For a series , let . If L < 1, the series converges. If L > 1, the series diverges. If L = 1, the test is indeterminate.