hp40g+.book Page 16 Friday, December 9, 2005 1:03 AM

DIFF menu

DERIV

Derivative and partial derivative

 

DERIV has two arguments: an expression (or a function)

 

and a variable.

 

 

 

DERIV returns the derivative of the expression (or the

 

function) with respect to the variable given as the second

 

parameter (used for calculating partial derivatives).

 

Example

 

 

 

 

 

 

 

 

 

Calculate:

 

 

 

 

 

 

 

 

 

∂(x ⋅ y2

 

⋅ z3

+ x ⋅ y)

 

 

---------------------------------------------

 

 

 

 

∂z

 

 

 

 

Typing:

 

 

 

 

 

 

 

 

 

DERIV(X·Y2·Z3 + X·Y,Z)

 

gives:

 

 

 

 

 

 

 

 

 

3 ⋅ x ⋅ y2 ⋅ z2

 

 

DERVX

Derivative

 

 

 

 

 

 

 

 

 

DERVX has one argument: an expression. DERVX

 

calculates the derivative of the expression with respect to

 

the variable stored in VX.

 

For example, given:

 

 

f(x) =

 

-------------

2

x

+ ln

⎛x-----------+ 1⎞

 

 

 

x

 

– 1

⎝ x – 1⎠

 

 

 

 

 

 

 

 

calculate the derivative of f.

 

Type:

 

 

 

 

 

 

 

 

 

ERVX⎛

--------------

 

X

+ LN⎛X------------+ 1⎞

 

⎝

X

2

– 1

⎝ X – 1⎠

 

 

 

 

 

 

 

Or, if you have stored the definition of f(x) in F, that is, if

 

you have typed:

 

 

⎛

 

 

 

X

 

⎛X + 1⎞

 

TORE⎝

X--------------

2

 

 

+ LN⎝------------X– 1⎠ ,F

 

 

 

 

 

– 1

 

then type:

14-16

 

 

Computer Algebra System (CAS)