答案:1. "Pythagorean Theorem and Trigonometry" by David A. Smith
2. "Trigonometry for Dummies" by Mary Jane Sterling
3. "The Pythagorean Theorem: A Primer" by John H. Conway
4. "Trigonometry: A Complete Course" by S. S. Khare
5. "Pythagorean Theorem: Easy Explanation" by Richard J. Trudeau