Duf(function, [varlist], [point], [direction])
[varlist]
If no value is given the default value is [x,y,z].

[point]
If given the directional derivative is calculated at that point. If not, then [x, y, z] is used.

[direction]
If given the derivative is calculated at the given point in the direction of the given vector. If no direction is given the vector [1, 1, 1] is assumed.

Description
Calculates the directional derivative of a given function.

Examples
Duf(x^2*y^2*z^2, [x, y, z], [1, 2, 3], [1, 1, -2])
60
6
Duf(x^2*y^2*z^2)
2
x
2
y
2
z
3
+
2
x
y
2
z
2
3
+
2
x
2
y
z
2
3
Duf(f(x, y, z))
D
(
f
(
x
,
y
,
z
)
,
x
)
3
+
D
(
f
(
x
,
y
,
z
)
,
y
)
3
+
D
(
f
(
x
,
y
,
z
)
,
z
)
3
Duf(x^2*y*z, [x, y, z], [1, -1, 1], [4, 0, -3])
-1
Duf(3x^2-3y^2, [x, y], [1, 2], [0, 1])
-12
Duf(sqrt(x^2+y^2), [x, y, z], [0, -2, 1], [2, 2, 1])
2
3
Duf(sin(x)+cos(y)+sin(z), [x, y, z], [#pi, 0, #pi], [#pi, #pi, 0])
-
π
2
abs
(
π
)
2

References
A
B
C
D
E
F
G
H
I
J
K
L
M
N
P
Q
R
S
T
V
W
Z