88 explainers

Knowledge base

The reasoning behind every calculator, written out. Each article names what you need to know first, works through the method, and says where it usually goes wrong — so you can get unstuck without asking anyone.

Method TrigonometryHow to Find Sine, Cosine and Tangent of an AngleEvery angle reduces to the same four moves: shrink it to one turn, find its quadrant, take the reference angle, then attach the sign.7 min read Concept TrigonometrySine, Cosine and Tangent: What They Are, PlainlySine, cosine and tangent are just three ratios of a triangle's sides. The unit circle extends them to every angle, and shows why the signs change.7 min read Mistakes Trigonometry5 Common Trig Mistakes and How to Catch ThemFour of the five are caught by one habit: check the sign against the quadrant, and the size against the reference angle.6 min read Examples TrigonometryTrig Examples: 8 Worked ProblemsEight angles, ordered so each one adds exactly one new idea to the last. Every value is checked against the sign of its quadrant.7 min read Mistakes Basic Math5 Common Scientific Notation MistakesFour of the five are caught the same way: move the decimal point back by the exponent and compare with where you started.6 min read Examples Basic MathScientific Notation Examples: 8 Worked ProblemsEight conversions, ordered so each one adds exactly one idea to the last. Every answer is checked by moving the decimal point back.7 min read