What it means
A prime after a function means its derivative: f′ is the first derivative and f″ the second. After a variable it marks a related but different value, as in s and s′ for the current and next state. In geometry and angles, ′ and ″ are minutes and seconds.
Read aloud in real formulas
f′(x) = 2x
Aethel says
f prime of x equals 2x
the derivative of f
y″ + y = 0
Aethel says
y double prime plus y equals 0
y's second derivative plus y is zero
Typing it
- LaTeX
- f', f''
- Unicode
- U+2032, U+2033
Formulas that use it
Questions
How do you say ′ out loud?
It is usually read “prime”, and also “double prime”.
What does ′ mean in maths?
A prime after a function means its derivative: f′ is the first derivative and f″ the second. After a variable it marks a related but different value, as in s and s′ for the current and next state. In geometry and angles, ′ and ″ are minutes and seconds.
How do you type ′?
In LaTeX, write f', f''. Its Unicode code point is U+2032, U+2033.