The Gradient
Definition (Gradient) Let
be a differentiable function at
and let
have partial derivatives
and
Then the gradient of
is denoted by
The value of the gradient at the point
is denoted by
![the gradient _gr_9.gif]](pages/the-gradient/Images/the-gradient_gr_9.gif)
Proposition (Gradient) Let
and
be differentiable functions. Then
(i)
for any constant
![the gradient _gr_13.gif]](pages/the-gradient/Images/the-gradient_gr_13.gif) (ii)
for any constants
and
![the gradient _gr_16.gif]](pages/the-gradient/Images/the-gradient_gr_16.gif) (iii)
![the gradient _gr_17.gif]](pages/the-gradient/Images/the-gradient_gr_17.gif) (iv)
provided
![the gradient _gr_19.gif]](pages/the-gradient/Images/the-gradient_gr_19.gif) (v)
![the gradient _gr_20.gif]](pages/the-gradient/Images/the-gradient_gr_20.gif) Proof. The Constant Rule is proved as follows:
The Linearity Rule is proved as follows:
![the gradient _gr_22.gif]](pages/the-gradient/Images/the-gradient_gr_22.gif)
![the gradient _gr_23.gif]](pages/the-gradient/Images/the-gradient_gr_23.gif)
The Product Rule is proved as follows:
![the gradient _gr_25.gif]](pages/the-gradient/Images/the-gradient_gr_25.gif)
![the gradient _gr_26.gif]](pages/the-gradient/Images/the-gradient_gr_26.gif)
![the gradient _gr_28.gif]](pages/the-gradient/Images/the-gradient_gr_28.gif)
![the gradient _gr_29.gif]](pages/the-gradient/Images/the-gradient_gr_29.gif)
The Quotient Rule is proved as follows:
![the gradient _gr_30.gif]](pages/the-gradient/Images/the-gradient_gr_30.gif)
![the gradient _gr_32.gif]](pages/the-gradient/Images/the-gradient_gr_32.gif)
![the gradient _gr_33.gif]](pages/the-gradient/Images/the-gradient_gr_33.gif)
![the gradient _gr_34.gif]](pages/the-gradient/Images/the-gradient_gr_34.gif)
The Power Rule is proved as follows:
![the gradient _gr_35.gif]](pages/the-gradient/Images/the-gradient_gr_35.gif)
![the gradient _gr_36.gif]](pages/the-gradient/Images/the-gradient_gr_36.gif)
![the gradient _gr_37.gif]](pages/the-gradient/Images/the-gradient_gr_37.gif)
![the gradient _gr_38.gif]](pages/the-gradient/Images/the-gradient_gr_38.gif)
Example (Gradient) Find the gradient of the function,
![the gradient _gr_40.gif]](pages/the-gradient/Images/the-gradient_gr_40.gif)
Solution. If
then
and
Recommended Reading
functions of several variables
graphs of functions
polynomial functions
rational functions
level curves
level surfaces
limits of multivariate functions
continuity of multivariate functions
partial derivatives
higher order partial derivatives
tangent planes
total differential
linear approximation with multivariate functions
differentiability
chain rule with one independent parameter
chain rule with two independent parameters
chain rule with several independent parameters
directional derivatives
the gradient
the gradient and directional derivatives
steepest ascent and steepest descent
normal property of the gradient
tangent planes and normal lines
relative extrema
critical points
second partials test
absolute extrema
lagrange multipliers with one parameter
lagrange multipliers with two parameters
Recommended Math Books
Thomas' Calculus, Early Transcendentals, Media Upgrade (11th Edition)
Thomas' Calculus, Media Upgrade (11th Edition)
Thomas' Calculus Early Transcendentals; Student's Solutions Manual; Part One
Calculus (With Analytic Geometry)(8th edition)
Calculus (Stewart's Calculus Series)
Applied Calculus
Calculus Textbooks
Elementary Calculus
Advanced Calculus
Supplementary Resources
Recommended Math Gifts
Math Happy
Calculus Happy
Homework Happy
Limits Happy
I Love Math
I Love Calculus
I Love Homework
I Love Multivariate Calculus
I Love Limits
Cite this as: The Gradient Published by Library of Math -- Online math organized by subject into topics.
Written by Smith, David A.
http://www.libraryofmath.com/the-gradient.html
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