Trig functions: cosec. sec. cot resources
Just the Maths (A.J.Hobson)
"Just the Maths" authored by the late Tony Hobson, former Senior Lecturer in Mathematics of the School of Mathematical and Information Sciences at Coventry University, is a collection of separate mathematics units, in chronological topic-order, intended for foundation level and first year degree level in higher education where mathematics is a service discipline e.g. engineering.