Same as first paragraph of MATH1151, albeit now with MATH1231/41. Note that MATH1251 learn two topics that the other two courses do not - functions of several variables, and double integrals
The aim of first year second semester mathematics is to take the now formalised concepts and start applying them to methods in mathematics. The shift in emphasis has resulted in a trend that students finding this course easier than the previous (however definitely not always the case). Only some knowledge of MATH1151 calculus is required for MATH1251 calculus, but all the algebra (excluding probability - used in ACTL1101) should be known here.
A step up in abstraction occurs in algebra, but a step down happens in calculus.