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HMMT 二月 2019 · 冲刺赛 · 第 1 题

HMMT February 2019 — Guts Round — Problem 1

专题
Discrete Math / 离散数学
难度
L3
来源
HMMT

题目详情

  1. [ 3 ] Find the sum of all real solutions to x + cos x = 2019.
解析
  1. [ 3 ] Find the sum of all real solutions to x + cos x = 2019. Proposed by: Evan Chen Answer: 0 The left-hand side is an even function, hence for each x that solves the equation, − x will also be a solution. Pairing the solutions up in this way, we get that the sum must be 0.