\left. \right.The \left. and \right. commands in LaTeX are used to create invisible delimiters. They are particularly useful when you want to match the size of delimiters without actually displaying them. This is often used in mathematical expressions where you need to align parts of the equation without showing additional symbols.
Evaluating a function at specific bounds without showing the left delimiter.
\left. x^2 \right|_{a}^{b}Partial derivative evaluated at a point, using invisible delimiters to match the size of the fraction.
\left( \frac{dy}{dx} \right)_{x=0}Definite integral with evaluation bar, using invisible delimiters to align the integral and evaluation bar.
\left. \int_a^b f(x) \, dx \right|