ผลต่างระหว่างรุ่นของ "รายชื่อเอกลักษณ์ลอการิทึม"

<math>\log_b \bigg(\frac{x}{y}\bigg) = \log_b(x y^{-1}) = \log_b(x) + \log_b(y^{-1}) = \log_b(x) - \log_b(y)</math>

 

 

<math>\log_b(\sqrt[y]x) = \log_b(x^{\frac{1}{y}}) = \frac{1}{y}\log_b(x)</math>

 

: <math>\log_b (a-c) = \log_b a + \log_b \left(1-\frac{c}{a}\right)</math>

 

have to be switched on the right hand side of the equations if <math>c>a</math>. Also note that the subtraction identity is not defined if <math>a=c</math> since the logarithm of zero is not defined. Many programming languages have a specific <code>log1p(x)</code> function that calculates <math>\log_e (1+x)</math> without underflow when <math>x</math> is small.