GCSE Maths Formulas

\( A = \tfrac{1}{2}ab\sin C \)

\( a^2=b^2+c^2-2bc\cos A \)

\( \text{radians}=\text{degrees}\times\tfrac{\pi}{180},\qquad \text{degrees}=\text{radians}\times\tfrac{180}{\pi} \)

\( \sin\theta=\tfrac{\text{opp}}{\text{hyp}},\quad \cos\theta=\tfrac{\text{adj}}{\text{hyp}},\quad \tan\theta=\tfrac{\text{opp}}{\text{adj}} \)

\( \frac{a}{\sin A}=\frac{b}{\sin B}=\frac{c}{\sin C} \)

\( \sin45^{\circ}=\cos45^{\circ}=\tfrac{\sqrt{2}}{2};\;\sin30^{\circ}=\tfrac{1}{2},\;\cos30^{\circ}=\tfrac{\sqrt{3}}{2};\;\sin60^{\circ}=\tfrac{\sqrt{3}}{2},\;\cos60^{\circ}=\tfrac{1}{2} \)

\( \sin^2\theta+\cos^2\theta=1,\quad \tan\theta=\tfrac{\sin\theta}{\cos\theta} \)