The given expression in the image is an integral:

$\int \tan(x) \, dx$

The integral of $\tan(x)$ with respect to $x$ is:

$\int \tan(x) \, dx = -\ln|\cos(x)| + C$

where $C$ is the constant of integration.

Would you like further details or any additional clarifications?

Here are some related questions to expand on this:

1. How is the integral of $\tan(x)$ derived?
2. What is the integral of $\sec(x)$, which is closely related to $\tan(x)$?
3. Can we use substitution to solve integrals like $\int \tan(x) \, dx$?
4. How is the logarithmic function involved in the integration of trigonometric functions?
5. What are other common integrals of trigonometric functions?

Tip: Always remember that logarithmic functions often arise when integrating trigonometric functions like $\tan(x)$ due to their derivative properties.