logarithmとは 意味・読み方・使い方

語源

From New Latin logarithmus, coined by Scottish mathematician John Napier from Ancient Greek λόγος (lógos, “ratio, proportion”) and ἀριθμός (arithmós, “number”). Napier set a geometric progression (a sequence of equal ratios) against an arithmetic progression (a sequence of equal differences), so that the logarithm of a number counts the ratios separating it from a starting value, turning multiplication into addition.

発音

• (英国発音) IPA: /ˈlɒɡ.ə.ɹɪ.ð(ə)m/, /ˈlɔɡ.ə.ɹɪ.ð(ə)m/
• (米国発音) IPA: /ˈlɑ.ɡə.ɹɪ.ð(ə)m/, /ˈlɑ.ɡəɹ.ɹɪ.ðəm/, /ˈlɑɡ.ə.ɹɪðm/, /ˈlɑɡ.əɹ.ɹɪðm/
• (Canada) IPA: /ˈlɑ.ɡə.ɹɪ.ð(ə)m/
• ハイフネーション: log‧a‧ri‧thm

名詞

logarithm (plural logarithms)

1. (mathematics) For a number ${\\\\displaystyle x}$, the exponent by which a given base number must be raised in order to obtain the power ${\\\\displaystyle x}$. Written ${\\\\displaystyle \\\\log _{b}x}$. For example, ${\\\\displaystyle \\\\log _{10}1000=3}$ because ${\\\\displaystyle 10^{3}=1000}$ and ${\\\\displaystyle \\\\log _{2}16=4}$ because ${\\\\displaystyle 2^{4}=16}$.

   For a currency which uses denominations of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, etc., each jump in the base-10 logarithm from one denomination to the next higher is either 0.3010 or 0.3979.

同意語

• log

派生語

参照

参考

Other terms used in arithmetic operations:

Advanced hyperoperations: tetration, pentation, hexation

• ln
• characteristic
• mantissa

アナグラム

• algorithm, mithralog