Numerical and graphical solutions to odes, Numerical solution of first-order ode – HP 48gII User Manual

Page 538

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Page 16-60

0 HERMITE, result: 1,

i.e., H

0

*

= 1.

1 HERMITE, result: ’2*X’,

i.e., H

1

*

= 2x.

2 HERMITE, result: ’4*X^2-2’,

i.e., H

2

*

= 4x

2

-2.

3 HERMITE, result: ’8*X^3-12*X’,

i.e., H

3

*

= 8x

3

-12x.

Numerical and graphical solutions to ODEs

Differential equations that cannot be solved analytically can be solved
numerically or graphically as illustrated below.

Numerical solution of first-order ODE

Through the use of the numerical solver (

‚Ï), you can access an input

form that lets you solve first-order, linear ordinary differential equations. The
use of this feature is presented using the following example. The method used
in the solution is a fourth-order Runge-Kutta algorithm preprogrammed in the
calculator.

Example 1 -- Suppose we want to solve the differential equation, dv/dt = -1.5
v

1/2

, with v = 4 at t = 0. We are asked to find v for t = 2.


First, create the expression defining the derivative and store it into variable
EQ. The figure to the left shows the ALG mode command, while the right-
hand side figure shows the RPN stack before pressing

K.


Then, enter the NUMERICAL SOLVER environment and select the differential
equation solver:

‚Ϙ @@@OK@@@ . Enter the following parameters:

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