1. Definitions
For any real numbers $a$, $b$, $c$ and $d$. Let $z=a+bi$, whe… Read
For any real numbers $a$, $b$, $c$ and $d$. Let $z=a+bi$, whe… Read
Let $T(1)$, $T(2)$, …, $T(n)$ be an arithmetic seque… Read
If $y \propto x$ (i.e. $y$ varies directly as $x$), then we ha… Read
For quadratic equation $ax^2+bx+c=0$, where $a$, $b$ and $… Read
When $f(x)$ is divided by $d(x)$, if the quotient is $Q(x)$ a… Read
The sequence of numbers $1$, $1$, $2$, $3$, $5$, $8$, $13$, $… Read
Let $T(1)$, $T(2)$, …, $T(n)$ be an geometric sequen… Read
Denote $O$ and $N$ the old value and new value respectively, … Read
The relation between the magnitude ($M$) of an earthquake a… Read
If $y \propto \frac{1}{x}$ (i.e. $y$ varies inversely as $x… Read
If $y$ varies directly as $x$ and inversely as $z$, then we ha… Read
For any real numbers $a$, $b$ and $c$, any rational numbers $… Read