How this calculation works
Translate an already established coefficient ratio limit into the radius of convergence.
THE FORMULA
R=1/L when L is positive and finiteA worked example
If the absolute coefficient ratio tends to 1/4, the radius is 4.
Good to know
This takes the limit as an input. Endpoints require separate analysis.
Reference: OpenStax Algebra and Trigonometry (opens in a new tab) ↗
Read the result
Translate an already established coefficient ratio limit into the radius of convergence.
The primary result is labeled “Radius of convergence”. Keep the input definitions in view when comparing this result with another method.
Try a related calculation
This takes the limit as an input. Endpoints require separate analysis.
For a related exercise, try the quadratic equation solver.
A few questions, answered
How can I check the default inputs by hand?
If the absolute coefficient ratio tends to 1/4, the radius is 4.
Which rule does this calculator apply?
R=1/L when L is positive and finite