a^{\prime}
The prime symbol (') is used as an accent in LaTeX to denote derivatives or to distinguish between similar variables. It is often used in mathematical expressions to indicate the first derivative of a function or to differentiate between related variables.
First derivative of a function f with respect to x
f^{\prime}(x) = \frac{d}{dx}f(x)
Variable a prime is defined as the sum of b and c
a^{\prime} = b + c
Position x prime as a function of initial position x and velocity v over time t
x^{\prime} = x + vt