數學 國中 約4年以前

求解QAQ 麻煩也告訴我各項正確或不正確的原因🙏🏻

DSE Assorted Exercises on Junior Secondary Topics 4. In AABC, ZC = 90°. Which of the following must be true? I. sin? A = cos B tan A II. tan C = tan B III. COS? C = cos? A + cos2 B A. I only Chapter 12 B. III only C. I and III only D. I, II and III