Self-teaching Algebra II and progressing to Trigonometry can be effectively supported through various online resources and textbooks. Many participants emphasize the abundance of free online materials, including Khan Academy, Coursera, and YouTube instructional videos, which can provide valuable insights and explanations. Textbooks are also recommended as a structured way to learn, with suggestions for specific titles that cover foundational math concepts. While Khan Academy is frequently mentioned as a popular resource, opinions vary regarding its effectiveness; some users find it beneficial, while others criticize its presentation and suggest alternative educators like Professor Leonard and others on platforms like iTunesU. The importance of a syllabus to guide learning and the need for practice through problem-solving are highlighted as essential components of self-study. Additionally, engaging with professors during office hours is suggested as a way to deepen understanding in physics and math. Overall, a combination of textbooks, online courses, and problem-solving practice is recommended for a well-rounded self-learning experience.