Standard definitions. Formulas, SI units, dimensional formulas and physical constants follow standard textbook and SI usage. Constants are given to the precision students use in class, with the more precise value where it matters.
Worked examples. Each example is solved in full and checked a second time. Calculators are tested with the page’s own examples.
Sign conventions. Where conventions differ between courses, as with mirrors and lenses, the page states which one it uses.
Formula sheets. Exam boards publish their own official formula sheets. Our formula sheet pages are study summaries and never claim to be official.
Corrections. Reported errors are checked and corrected, and the page’s updated date changes.
Advertising is clearly separated from the content and never changes what a page says.