Dr. Kevin G. TeBeest
You should always perform 3 or 4 iterations of my classroom example(s) BEFORE attempting the homework.
- Clearly and precisely write the Intermediate Value Theorem.
- What is the rate of convergence of the bisection method? I.e., is it linear, quadratic, cubic?
- The function f(x) = 2sin(x) 1/4*exp(x) has two zeros near x = 5.
- Using a starting interval [7, 5], apply 6 iterations of the bisection method to approximate one the zeros.
- Using a starting interval [5, 3], apply 6 iterations of the bisection method to approximate the other zero.
- Write this Maple code for the bisection method.
Then use your working code to do both parts of problem 3 above, and iterate until your approximation has converged to 5 digits.
Write this code as soon as possible and save it, because you will use it as a template (model) for Programming Assignment 1.
- See what happens if you rework the example from lecture but using a starting interval [1, 9]. What do the iterates converge to?
After working this problem, see the answers here.
- Read and do the Maple example for using Maple's fsolve command to approximate a zero of a function.
Then use Maple's fsolve command to approximate the zeros in problem 3 above.
- See the Bisection Method Algorithm (pseudocode).
- What is the other name of the bisection method?
Do the following AFTER we discuss the error analysis of the bisection method on Thursday.
- If we use the bisection method to approximate a zero of a function on the interval [2,3], what is the error bound after 12 iterations?
Answer: The error of the 12th iterate xm is guaranteed to be no greater than 0.001220703... units.
- If we use interval halving to approximate a zero of a function on the interval [2,3], how many iterations should be performed to obtain at least 12 decimal place accuracy in our approximation?
Answer: 44 iterations guarantees at least 12 decimal place accuracy. OR: the 44th iterate is guaranteed to be correct (agrees with the correct value of zero z) to at least 12 decimal places.
- For the function
f (x) = e–x – cos x,use the bisection method's error bound formula to determine the number of iterations required to guarantee that we would approximate a zero with an accuracy of at least 7 decimal places if we were to start on the interval [2,7].
NOTE: Use the error bound formula only — do NOT actually apply the bisection method to answer the question.
Answer: 27 iterations guarantees at least 7 decimal place accuracy. OR: the 27th iterate is guaranteed to be correct (agrees with the correct value of zero z) to at least 7 decimal places.
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