4 resources.
Sine, cosine, tangent and their reciprocals, standard angle values, the core identities, and solved examples on ratios, identities, co-functions and product-to-sum.
Integrating trig functions with power-reduction and product-to-sum identities: a table of identities, four worked examples and common mistakes.
Inverse trigonometric functions: principal value ranges, evaluating expressions, domains, the identities tan⁻¹x + cot⁻¹x = π/2 and a sum of arctangents, with worked examples and common mistakes.
What a radian measures, converting degrees, minutes and radians, a standard-angle table, and arc length and sector area in radians, with worked examples.