初中数学若x+y+2xy=18求x+y(这样解是不是更巧妙?) #初中数学 - 远舟数学于20230302发布在抖音,已经收获了484个喜欢,来抖音,记录美好生活!
Solvex2y"+7xy′−18y=0. Question: x2y"+7xy′−18y=0 Euler's Differential Equation: The differential equation when represented in the form of: x2y″+axy′+by=0 where a and b are the constants, is known as the second order Euler's differential equation. This type of differential...
已知2xy=18，xy=9=1×9=2×4.5=3×3=4×2.25 所以，x+y的最小值=3十3=6
WzTy116TCiRjTSxWQ2xyvpq2hIpDqHPQ8INjl+U9XR66P9bj7cC47K9sf8xRNlr27tK1b 61Pyy3AvvR5+rwJsPOWqELlYEervYSVyg2c1ILdJHel+tkv90mxCbdPRaiYeQiT2h6gh3/bVmS5R qRnBgu5OT8L+8xWN7Y7TzdYtOlY1Dtll0XTFsTOjM1byK828M1MwRVMcSacYWfYpTo8BFVo3SB7C 1gwoUxSkZugnul/zxo8p9DUAtNHmy52Y61Ts8JeaCF+...
解析 【解析】证明: x0,y0; x+2y≥2/2xy; 故2/2xy≤18; 故xy,当且仅当x=2y时取等号; 综上所述,答案为:证明成立 结果一 题目 7.已知 x0 , y0 ,x+2y=18,求证:xy≤(81)/2 答案 7. ∵x0y0 且x+2y=18, ∴xy=1/2x⋅(2y)≤1/2⋅((x+2y)/2)^2=1/2*9^2=(81)/2相关推荐...
7746VxuDfp8Xl3THEPHFpZknV3g4ZYNXvrONXb2Y5iafmF11NZIc4cu sc5bZTpra4WWpaiza2prjNOdak0t1HWLOsZIO/f2UyeNtlXXSbM+383abnW8MWPZeJxyuUw3PjPO +9ljXM4S7mXinG9Hz/U7BukxCI9GD/Xmfr855zE27yYL89LOZg9e1eBdY/sYg6eWQ4i3cN748M6+ hDp3jL25S9up0tndfG/otqbujuauyzr9AsPuQcnMJUtEBMBs+vGljum8jkYaT...
如果不怕看错，那就不设y，直接用1/x进行计算也行。【解】设：y=1/x，则有：xy=1，原式可化成：x²+y²-3x-3y+2=0 (x²+y²+2)+(-3x-3y)=0 (x²+y²+2xy)-3(x+y)=0 (x+y)²-3(x+y)=0 (x+y)(x+y-3)=0 因为：x+1/x...
已知x+y+2xy=18,x、y是整数,求x+y的值。 - 岁月静好于20240524发布在抖音,已经收获了10.9万个喜欢,来抖音,记录美好生活!
We read every piece of feedback, and take your input very seriously. Include my email address so I can be contacted Cancel Submit feedback Saved searches Use saved searches to filter your results more quickly Cancel Create saved search Sign in Sign up Reseting focus {...
2√(2xy)≤x+2y=18 √(2xy)≤9 2xy≤81 xy≤81/2