HP F2226A - 48GII Graphic Calculator User Manual page 487

Next, we can write
dy/dx = (C + exp x)/x = C/x + e
In the calculator, you may try to integrate:
'd1y(x) = (C + EXP(x))/x' ` 'y(x)' ` DESOLVE
The result is { 'y(x) = INT((EXP(xt)+C)/xt,xt,x)+C0' }, i.e.,
Performing the integration by hand, we can only get it as far as:
y
because the integral of exp(x)/x is not available in closed form.
Example 3 – Solving an equation with initial conditions. Solve
with initial conditions
In the calculator, use:
['d1d1y(t)+5*y(t) = 2*COS(t/2)' 'y(0) = 6/5' 'd1y(0) = -1/2'] `
Notice that the initial conditions were changed to their
= 6/5', rather than 'y(0)=1.2', and 'd1y(0) = -1/2', rather than, 'd1y(0) = -
0.5'. Changing to these Exact expressions facilitates the solution.
Note: To obtain fractional expressions for decimal values use function
(See Chapter 5).
x
e + C
y ( x ) = ⋅ dx +
x
x
e
( x ) dx C ln
x
2 2
d y/dt + 5y = 2 cos(t/2),
y(0) = 1.2, y'(0) = -0.5.
'y(t)' `
DESOLVE
x
/x.
C
0
x C
0
Exact expressions, 'y(0)
Page 16-9
Q