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Article 11 — Appendix A.23ln — natural logarithmic functionCategory. Mathematics. Abstract. Natural logarithm: definition, graph, properties and identities. References. This article is a part of scientific calculator LiL, scientific calculator LiX, scientific calculator LiLc and scientific calculator LiXc products. 1. DefinitionNatural logarithmic function is the inverse of the exponential function. 2. GraphNatural logarithmic function is defined on positive part of the real axis — so, its domain is (0, +∞). 0 is singular point. Function graph is depicted below — fig. 1. Fig. 1. Graph of the natural logarithmic function y = lnx.Function codomain is entire real axis. 3. IdentitiesBy definition: ln e^{x} ≡ xReciprocal argument: ln(1/x) = −lnxProduct and ratio of arguments: ln(xy) = lnx + lnyln(x /y) = lnx − lny Power of argument: lnx^{a} = a lnxBase change: log_{a}x = lnx /lnalog_{a}x = log_{b}x /log_{b}a 4. SupportNatural logarithmic function ln is supported in: Natural logarithmic function of the complex argument ln is supported in:
5. How to useTo calculate natural logarithm of the number:
To calculate natural logarithm of the current result:
To calculate natural logarithm of the number x in memory:



