PC / Advanced
Precalculus
Orbit Observatory
Connect functions, trigonometry, complex numbers, vectors and linear transformations.
Preparation: Intermediate algebra, coordinate geometry, radicals and function notation.
Current coverage: 12 core stages covering domains, trigonometric identities, polar coordinates and 2D/3D vector methods.
LEVEL 1 · DIFFICULTY 1/5 within this course
Functions and Circular Measurement
Connect domains, radians and coordinates.
Explore 3 knowledge islands
Choose an island to read its lesson.
3 stages · 24 library problems · 108 checked variations · 2 × 6 assessment questions
Read the lessons →LEVEL 2 · DIFFICULTY 2/5 within this course
Trigonometric Relationships
Combine rotations and solve nonright triangles.
Explore 3 knowledge islands
Choose an island to read its lesson.
3 stages · 24 library problems · 108 checked variations · 2 × 6 assessment questions
Read the lessons →LEVEL 3 · DIFFICULTY 3/5 within this course
Polar, Complex and Vector Coordinates
Use coordinate systems suited to the problem.
Explore 3 knowledge islands
Choose an island to read its lesson.
3 stages · 24 library problems · 108 checked variations · 2 × 6 assessment questions
Read the lessons →LEVEL 4 · DIFFICULTY 4/5 within this course
Matrices and Space
Measure orientation and describe planes.
Explore 3 knowledge islands
Choose an island to read its lesson.
3 stages · 24 library problems · 108 checked variations · 2 × 6 assessment questions
Read the lessons →Progress earned through practice
Earn two independent practice stars and one application star, then complete the library skill check for that stage. The check covers the stage’s library prompts, so changing numbers alone is not enough. Hints help you learn; your existing stars and earned rewards stay yours. Clear every stage to clear a level.
Every stage includes an explanation, two worked examples and eight library practice problems, plus checked variations with changing numbers and applications. Each level also has a separate unit test and a later review form. Parents see actual attempts, hint use and results.
These are independently authored core-skills courses, with the current scope listed for each course. They do not reproduce complete textbook contents. Difficulty describes the teaching sequence within each course; course preparation matters when comparing subjects. This site is not affiliated with or endorsed by AoPS. Results reflect these exercises and are not standardized scores. Content release math-courses-2026.09.27-university-guides-v2.