Calculus Volume 2 · free preview

Ratio and Root Tests

The ratio test examines successive term ratios and the root test the nth roots, each certifying absolute convergence when the limit is below 1 and diverging above 1, the mechanical workhorses for factorials and exponentials.

1. The ratio test

The ratio test

2. The root test

The root test

3. Choosing and combining

Choosing and combining

4. The toolkit assembled

The toolkit assembled

5. Ratio test verdict

The ratio test computes rho as the limit of |a_(n+1)/a_n|. Which rho certifies absolute convergence?

6. Factorial growth verdict

The series sum of 2^n/n! converges by which observation?

7. Root test best case

The root test is most directly suited to series whose terms have which structure?

8. Boundary inconclusiveness

Both ratio and root tests are inconclusive at rho = 1. Which series illustrates this boundary behaving differently?

9. Factorial over exponential

The series sum of n!/100^n diverges by which ratio test computation?

10. Ratio for n over 2^n

For sum of n/2^n, the ratio of successive terms is (n + 1)/(2n), tending to what number? Answer with a fraction like 1/2.

11. Root for third power

For sum of (1/3)^n, the nth root of the nth term equals what number? Answer with a fraction like 1/3.

12. Boundary name

The ratio and root tests both decline at rho = 1, and the tests are said to be what? Answer with one word.

13. Root test on n-th power terms

The series sum of (3n/(2n + 1))^n has nth root tending to what value?

14. Test target

Both the ratio and root tests certify which kind of convergence when successful? Answer with one word.

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