Teach.sg ← Back to Mathematics

Power, Exponential, Logarithmic & Modulus Functions

🦉 Modulus Functions
For $|a| = b \Rightarrow a = b$ or $a = -b$.
🦉 Logarithm Definition
For $\log_a y$ to be defined,
$$1.\,y > 0$$
$$2.\,a > 0, a \neq 1$$
🦉 Laws Of Logarithms
$$1.\,\log_a x^n = n\log_a x$$
$$2.\,\log_a xy = \log_a x + \log_a y$$
$$3.\,\log_a \frac{x}{y} = \log_a x - \log_a y$$
$$4.\,\log_a b = \frac{\log_c b}{\log_c a}$$
$$5.\,\log_a b = \frac{1}{\log_b a}$$
🦉 Logarithms To Exponential
$$x = \log_a y \Leftrightarrow y = a^x$$
$$\lg y = x \Leftrightarrow y = 10^x$$
$$\ln y = x \Leftrightarrow y = e^x$$