How do you simplify ln(1e3)? Precalculus Exponential and Logistic Functions The Natural Base e 1 Answer Bill K. Dec 3, 2015 ln(1e3)=ln(e−3)=−3. Explanation: Since ln(x) and ex are inverse functions, ln(ex)=x for all values of x. Since 1e3=e−3 by definition of negative exponents, it follows that ln(1e3)=ln(e−3)=−3. You could also note that ln(1e3)=ln(1)−ln(e3)=0−3=−3 since ln(AB)=ln(A)−ln(B) and ln(1)=0. Answer link Related questions What is base e? What are common mistakes students make with base e? What is the value of e? What is Euler's number? What is the significance of Euler's number? What does Euler's number represent? How do I work with Euler's number in Excel? How do I find the inverse of ex? How does e relate to π? Is the number e rational or irrational? See all questions in The Natural Base e Impact of this question 16049 views around the world You can reuse this answer Creative Commons License