It sounds like you're referring to — likely from the Kumon Math Program.
Level O focuses on high-level mathematical concepts equivalent to late high school or early university material: kumon level o
Unlike standard school curriculums which may rush through these topics, Level O demands a high degree of computational fluency and logical derivation. The level is notorious among Kumon students for its length and difficulty, serving as a "weeding out" point where only students with strong self-discipline and foundational skills succeed. It sounds like you're referring to — likely
: Integration by parts and using substitution for complex functions. : Integration by parts and using substitution for
In the Kumon Math program, is the final level of the standard curriculum, primarily covering advanced calculus and differential equations . Completing Level O and passing its achievement test marks the official completion of the Kumon Math program, making a student a "Kumon Completer". Key Topics in Level O