C
C[i]
is the default form for the i 
parameter or constant generated in representing the results of various symbolic computations.
C
C[i]
is the default form for the i 
parameter or constant generated in representing the results of various symbolic computations.
Details
- The C[i] are often used to parameterize families of solutions to equations.
- In functions like DSolve, the C[i] can be thought of as corresponding to constants of integration.
- In cases such as partial differential equations, the C[i] represent functions rather than variables.
- C is the default setting for the option GeneratedParameters in such functions as DSolve, RSolve, and Reduce.
Wolfram Research (1991), C, Wolfram Language function, https://reference.wolfram.com/language/ref/C.html (updated 2003).
Text
Wolfram Research (1991), C, Wolfram Language function, https://reference.wolfram.com/language/ref/C.html (updated 2003).
CMS
Wolfram Language. 1991. "C." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2003. https://reference.wolfram.com/language/ref/C.html.
APA
Wolfram Language. (1991). C. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/C.html