The quadratic equation:

y \propto x \rightarrow y = \textcolor{limegreen}{k}x

y \propto x^2 \rightarrow y = \textcolor{limegreen}{k}x^2

y \propto \dfrac{1}{x} \rightarrow y = \dfrac{\textcolor{limegreen}{k}}{x}

y \propto \dfrac{1}{x^2} \rightarrow y = \dfrac{\textcolor{limegreen}{k}}{x^2}

Circumference =c=2\pi r=\pi d

Area =A=\pi r^{2}

Volume of a pyramid =\dfrac{1}{3}\times\text{ area of base }\times\text{ vertical height }

Volume of sphere =\dfrac{4}{3}\pi r^{3}

Surface area of sphere =4\pi r^{2}

Volume of cone =\dfrac{1}{3}\pi r^{2}h

Curved surface area of cone =\pi rl where l is the slant height

\sin(x) = \dfrac{\text{opp}}{\text{hyp}}\,\,\,\, \cos(x) = \dfrac{\text{adj}}{\text{hyp}}\,\,\,\, \tan(x) = \dfrac{\text{opp}}{\text{adj}}

Cosine Rule: \textcolor{red}{a}^2=\textcolor{limegreen}{b}^2+\textcolor{blue}{c}^2-2\textcolor{limegreen}{b}\textcolor{blue}{c}\cos \textcolor{red}{A}

or

\cos(\textcolor{red}{A}) = \dfrac{\textcolor{limegreen}{b}^2+\textcolor{blue}{c}^2 - \textcolor{red}{a}^2}{2\textcolor{limegreen}{b}\textcolor{blue}{c}}

\text{New value} = \text{original}\times \bigg(1 +\dfrac{\text{percentage}}{100} \bigg)^{\text{time}}

\text{New value} = \text{original}\times \bigg(1 -\dfrac{\text{percentage}}{100} \bigg)^{\text{time}}

\dfrac{\text{percentage}}{100} \times \text{amount}

\text{Percentage Change }= \dfrac{\text{new} - \text{original}}{\text{original}} \times 100

\text{Frequency Density }= \dfrac{\text{frequency}}{\text{class width}}

\begin{aligned}P(A\text{ or }B)&=P(A)+P(B)-P(A\text{ and }B)\\P(A\text{ and }B)&=P(A\text{ given }B)P(B)\end{aligned}

s= distance

u= start speed

v= end speed

a= acceleration

t= time