HP 39G

Using mathematical functions 10-23
Finding derivatives
The HP 39G/40G can perform symbolic differentiation on
some functions. There are two ways of using the HP 39G/40G
to find derivatives.
• You can perform differentiations in HOME by using the
formal variables, S1 to S5.
• You can perform differentiations of functions of X in the
Function aplet.
To find
derivatives in
HOME
To find the derivative of the function in HOME, use a formal
variable in place of X. If you use X, the differentiation
function substitutes the value that X holds, and returns a
numeric result.
For example, consider the function:
1. Enter the differentiation function onto the command line,
substituting S1 in place of X.
>GG[@>$/3+$@S1
>@>6,1@>$/3+$@S1
>[@ >@>@2 >[@
>&26@>$/3+$@S1
>@ >@
2. Evaluate the function.
>(17(5@
3. Show the result.
*k,
6+2:_
dx x(
2
)sin( 2 x())cos+
HP 39G
HP 40G