Multivariable Calculus

Multivariable Calculus explores functions of multiple variables, including partial derivatives, multiple integrals, and vector calculus.

Basic Concepts

Functions of Several Variables

Understanding Multivariable Functions

A function of several variables is a rule that assigns a single output to each combination of inputs from two or more variables. Unlike single-variable calculus, where inputs are just points on a line, multivariable functions map points from planes or higher-dimensional spaces.

Visualizing in Two and Three Dimensions

Imagine the temperature across a metal plate. The temperature at any point depends on both its \(x\) and \(y\) coordinates. This can be described by a function \(T(x, y)\). In three dimensions, functions like \(f(x, y, z)\) can represent things like air pressure in a room.

Domain and Range

  • The domain is the set of all possible input tuples \((x, y, ...)\).
  • The range is the set of all possible outputs.

Graphs and Level Curves

Graphing these functions often involves 3D plots or contour maps. Level curves are lines where the function has the same value, like the rings on a topographic map.

Real-Life Connections

Functions of several variables model phenomena like weather, economics, and engineering systems.

Examples

  • The elevation at each point on a hiking trail is a function \(z = f(x, y)\), where \((x, y)\) is your location.

  • A bakery's profit depending on the number of cupcakes and cookies sold can be modeled with \(P(c, k)\).

In a Nutshell

A function of several variables takes two or more inputs and gives one output, mapping across planes and higher dimensions.

Key Terms

Level Curve
A curve along which a function of two variables has a constant value.
Domain
All input values for which a function is defined.