白熹晴的个人资料 - RAT

白熹晴白熹晴

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求助西南医科大学饭卡，一直到考研结束，只用于进出图书馆！诚心求助西南医科大学饭卡，一直到考研结束，只用于进出图书馆！诚心！489469925

虚心请教，用理正计算重力式挡墙土压力后，得到的图像怎么分析？如图，我想得到该直线上，每一点的横纵坐标，应该怎么办呢？只能目测吗？

麻烦各位帮忙看一下解的这个三角函数方程有错吗？我先用solve解的我最终想得到的是角度所以用了Degree Solve[-2.88 Sin[x Degree ]*Sin[x Degree] - 3.026 Cos[x Degree]*Cos[x Degree] + 9.667 Cos[x Degree ] + 9.356 Sin[x Degree ] + 0.068 Sin[x Degree ]*Cos[x Degree] - 0.436 == 0, x] 解出来得到了四个解 {{x -> -69.1972 - 293.326 I}, {x -> -69.1972 + 293.326 I}, {x -> -31.0633}, {x -> 119.51}} 有两个貌似是虚数结果就提示我 Solve::ifun: Inverse functions are being used by Solve, so some solutions may not be found; use Reduce for complete solution information. 然后我就用了约化reduce Reduce[-2.88 Sin[x Degree ]*Sin[x Degree] - 3.026 Cos[x Degree]*Cos[x Degree] + 9.667 Cos[x Degree ] + 9.356 Sin[x Degree ] + 0.068 Sin[x Degree ]*Cos[x Degree] - 0.436 == 0, x] 结果也得到了四个解 C[1] \[Element] Integers && (x == 57.2958 (-0.542156 + 6.28319 C[1]) || x == 57.2958 (2.08584 + 6.28319 C[1]) || x == 57.2958 ((-1.20772 - 5.11951 I) + 6.28319 C[1]) || x == 57.2958 ((-1.20772 + 5.11951 I) + 6.28319 C[1])) 结果提示我Reduce::ratnz: Reduce was unable to solve the system with inexact coefficients. The answer was obtained by solving a corresponding exact system and numericizing the result. 我的问题最主要是能不能Solve得到的解和Reduce得到的解能不能等价呢按照题目规定的条件x是实数且为正数所以就直接舍去了其他三个那剩下的一个我应该用Reduce的还是solve的或者说我这个方法是不是错了跪求大神解答!!!

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