Wrong output when using random numbers

Question

Craig Muir 2019 年 6 月 19 日

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https://jp.mathworks.com/matlabcentral/answers/467914-wrong-output-when-using-random-numbers

コメント済み: Stephen23 2019 年 6 月 19 日

I'm attempting to satisfy an equation using 10 random numbers in the range [-pi,pi]. The results tend to be in an odd format and only one of the values ever seems to match, suggesting that something is going wrong. My attempt is below, any help would be apprectiated :).

x = (rand(10,1) * 2 - 1) * pi
y1 = (3*cot(x)-(cot(x).^3))/(1 - 3*(cot(x).^2)) 
y2 = cot(3*x)
y1 =
  Columns 1 through 7
         0         0    0.0047         0         0         0         0
         0         0   -0.0395         0         0         0         0
         0         0   -2.6571         0         0         0         0
         0         0    0.0034         0         0         0         0
         0         0    0.0047         0         0         0         0
         0         0    0.0082         0         0         0         0
         0         0   -0.0068         0         0         0         0
         0         0    0.0095         0         0         0         0
         0         0   -0.0573         0         0         0         0
         0         0    0.1041         0         0         0         0
  Columns 8 through 10
         0         0         0
         0         0         0
         0         0         0
         0         0         0
         0         0         0
         0         0         0
         0         0         0
         0         0         0
         0         0         0
         0         0         0
y2 =
   -1.4220
   -0.4570
   -2.6571
   -0.8258
   -1.4221
    0.4081
   -0.2741
    0.7070
   -0.5596
    0.7511