it might be a stupid question but I cannot see where the mistake is in this code:





H_{0}:\rho_{1}<0\text{ and }\rho_{2}>0
H_{A}:\rho _{1}\geqslant 0\text{and/or}\rho _{2}\leqslant 0.  \label{12}


I got an error message saying "Undefined control sequence". Can someone help me? Thanks in advance.

  • 1
    What's the rest of the message? It should indicate which command it doesn't recognise. (See the image at the top this answer which shows an undefined control sequence error followed by the debugging information.) Jun 18, 2016 at 12:32

1 Answer 1


The undefined control sequence is \text, which is defined by package amstext, which is automatically loaded by amsmath. Thus, the minimal


or the more powerful


fixes the issue.


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