1550078481-Ordinary_Differential_Equations__Roberts_

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96 Ordinary Differential Equations


c. Estimate the maximum discretization error p er step on the interval

[O, l] for the stepsize h = .1.

d. How small must the stepsize be in order to ensure six decimal
place accuracy p er step?


  1. a. Compute a n approximate solution to the initial value problem


y' = x^2 - y; y(O) = 1 on the interval [O, l] using Euler's method

and a const ant stepsize of h = .1.

b. Find an upper bound for the total discretization error at x = l.

c. How small must the stepsize be to ensure six decimal place
accuracy per step?
d. How small must the stepsize be to ensure six decimal place
accuracy over the interval [O, l ]?


  1. Use the improved Euler's formula with a stepsize h = .1 to generate a


numerical approximation to the solution of the IVP y' = x^2 -y; y(O) = 1


on the interval [O, l].

4. Use the modified Euler's formula with a stepsize h = .1 to generate a

numerical a pproximation to the solution of the IVP y' = x^2 -y; y(O) = 1

on the interval [O, l].

5. Use the fourth order Runge-Kutta formula with a stepsize h = .l

to generate a numerical approximation to the solut ion of the IVP y' =

x^2 - y; y(O) = 1 on the interval [O, l].

6. a. Find t he exact solution of the initial value problem y' = x^2 - y;

y(O) = l.

b. Compare the va rious approximate solutions generated in exer-
cises 1-5 with each other and the exact solution by producing a
t able of values.


  1. Consider the general recursive formula (16). Suppose that in addition
    to satisfying equations (20), we require that the coefficients of j2 fyy in
    equations (17) and (19) b e equal. What is the solution of the resulting
    syst em of four equa tions in the four unknowns a, b, c, and d?

  2. Generate a numerical solutions to the IVP y' = y/x + 2; y(l) = 1 on
    the interval [l, 2] with a stepsize of h = .05 using


a. Euler's method.
b. improved Euler's method.
c. modified Euler's method.
d. the fourth order Runge-Kutta method.
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