- cancellation law - see Extra - Sets and mappings - Important sets of numbers
- cardinality - see Extra - Sets and mappings - Mappings
- Carthesian product - see Extra - Sets and mappings - Basic set theory
- catenary (curve) - see Integrals - Methods Survey - Applications - Curve length
- Cauchy's condensation test - see Series - Theory - Testing convergence - More tests
- Cauchy product of series of real numbers - see Series - Theory - Introduction - Basic properties
- Cauchy sequence - see Sequences - Theory - Limit - Basic properties
- Cauchy's test - see Ratio test in Series - Theory - Testing convergence - Root and Ratio test and Series - Methods Survey - Testing convergence - Ratio test
- Cauchy's theorem - see Derivatives - Theory - MVT - MVT and comp.
- center of gravity - see Integrals - Theory - Applications - Mass and center of gravity
- chain rule (derivative) - see Derivatives - Theory - Introduction - Derivative and operations
- characteristic function
**1**_{M}(*x*) - see Functions - Theory - Elementary functions - Identity function - circle
- closed set - see Functions - Theory - Real numbers - Topological notions
- closure of a set - see Functions - Theory - Real numbers - Topological notions
- clusterpoint - see Functions - Theory - Real numbers - Topological notions
- combinatorial number - see Functions - Theory - Elementary functions - Factorial, binomial coefficients
- commutative law - see Extra - Sets and mappings - Important sets of numbers
- commutative law for series - see Series - Theory - Introduction - Basic properties
- comparison for functions and limits - see Functions - Theory - Limit - Comparison and Functions - Methods Survey - Limit - Comparison and oscillation
- comparison for improper integrals - see Integrals - Theory - Improper integrals - Convergence tests
- comparison for sequences - see Sequences - Theory - Limit - Comparison and Sequences - Methods Survey - Limit - Comparison and oscillation
- comparison of sets - see Extra - Sets and mappings - Basic set theory
- comparison test for improper integrals - see Integrals - Theory - Improper integrals - Convergence Tests
- comparison test for series - see Series - Theory - Testing convergence - Comparison tests and Series - Methods Survey - Testing convergence - Comparison tests
- complement - see Extra - Sets and mappings - Basic set theory
- completing a square - see Extra - Completing a square
- complex form of Fourier series - see Series - Theory - Series of functions - Properties of Fourier series
- complex numbers - see Extra - Sets and mappings - Important sets of numbers
- composition and sequences of functions - see Series - Theory - Series of functions - Sequences of functions and Series - Theory - Series of functions - Sequences of functions
- composition of mappings - see Extra - Sets and mappings - Mappings
- composition of functions - see Functions - Theory - Real functions - Operations
- concave up/down function - see concavity of functions
- concavity of functions
- conditional convergence of series - see Series - Theory - Introduction - Absolute convergence
- constant function - see Functions - Theory - Elementary functions - Polynomials
- constant sequence - definition in Sequences - Theory - Introduction - Important examples, properties in Sequences - Theory - Limit - Important examples
- continuity
- convergence of Fourier series - see Series - Theory - Series of functions - Fourier series
- convergence of Taylor series - see Series - Theory - Series of functions - Taylor series
- convergence tests for improper integrals - see Integrals - Theory - Improper integrals - Convergence tests and Integrals - Methods Survey - Improper integrals
- convergence tests for sequences of functions - see Series - Methods Survey - Series of functions - Sequences of functions
- convergence tests for series of functions - see Series - Methods Survey - Series of functions - Series of functions
- convergence tests for series of numbers - see Series - Theory - Testing convergence and Series - Methods Survey - Testing convergence
- convergent limit of a function - see Functions - Theory - Limit - Definition
- convergent integral - see Integrals - Theory - Improper integrals - Introduction
- convergent sequence - see Sequences - Theory - Limit - Definition, and functions: Sequences - Theory - Limit - Sequences and functions
- convergent sequence of functions - see Series - Theory - Series of functions - Sequences of functions
- convergent series of functions - see Series - Theory - Series of functions - Sequences of functions
- convergent series of real numbers - see Series - Theory - Introduction - Introduction
- convex function - see concavity of functions
- convolution of sequences - see Sequences - Theory - Introduction - Operations
- cos
- cosine Fourier series - see Series - Theory - Series of functions - Fourier series and Series - Methods Survey - Series of functions - Expanding in Fourier series
- cosh
- cot
- coth
- countable sets - see Extra - Sets and mappings - Mappings
- cover-up method for partial fractions - see Integrals - Methods Survey - Methods of integration - Partial fractions
- critical point - see Derivatives - Theory - Graphing function - Monotonicity and Derivatives - Theory - Methods Survey - Monotonicity
- csc (cosecant)
- curves