Logarithm/Integration of hyperbola/Function equation/Exercise

Prove the relationship

${}\int _{1}^{ab}{\frac {1}{x}}dx=\int _{1}^{a}{\frac {1}{x}}dx+\int _{1}^{b}{\frac {1}{x}}dx\,$

for ${}a,b\in \mathbb {R} _{+}$,

only using rules for integration.

Create a solution