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Wrong output when using random numbers

Asked by Craig Muir on 19 Jun 2019
Latest activity Commented on by Stephen Cobeldick on 19 Jun 2019
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
Granted the values change each time, it seems that one always seems to work and I'm not entirely sure why.

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1 Answer

Answer by madhan ravi
on 19 Jun 2019
 Accepted Answer

./ % this is why? see Array vs. Matlab operations [Google it]