HMMT 二月 2003 · 代数 · 第 2 题
HMMT February 2003 — Algebra — Problem 2
题目详情
- Compute . 2 2 ◦ ◦ tan (20 ) sin (20 )
解析
- Compute . 2 2 ◦ ◦ tan (20 ) sin (20 ) Solution: 1 2 2 ◦ ◦ If we multiply top and bottom by cos (20 ), the numerator becomes sin (20 ) · (1 − 4 4 2 ◦ ◦ ◦ cos 20 ) = sin (20 ), while the denominator becomes sin (20 ) also. So they are equal, and the ratio is 1.