![]() |
Prev | Next | ExpForward | Headings |
F(x) = \exp(x)
\[
1 * F^{(1)} (x) - 1 * F (x) = 0
\]
and in the
standard math function differential equation
,
A(x) = 1
,
B(x) = 1
,
and
D(x) = 0
.
We use
a
,
b
,
d
,
and
z
to denote the
Taylor coefficients for
A [ X (t) ]
,
B [ X (t) ]
,
D [ X (t) ]
,
and
F [ X(t) ]
respectively.
It now follows from the general
Taylor coefficients recursion formula
that for
j = 0 , 1, \ldots
,
\[
\begin{array}{rcl}
z^{(0)} & = & \exp ( x^{(0)} )
\\
e^{(j)}
& = & d^{(j)} + \sum_{k=0}^{j} a^{(j-k)} * z^{(k)}
\\
& = & z^{(j)}
\\
z^{(j+1)} & = & \frac{1}{j+1} \frac{1}{ b^{(0)} }
\left(
\sum_{k=1}^{j+1} k x^{(k)} e^{(j+1-k)}
- \sum_{k=1}^j k z^{(k)} b^{(j+1-k)}
\right)
\\
& = & \frac{1}{j+1}
\sum_{k=1}^{j+1} k x^{(k)} z^{(j+1-k)}
\end{array}
\]