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I have this simple equation to solve (1 == 62.5*E^(-30*10^6/x), {x}), and Mathematica is able to give a correct answer. However, there is this warning message (warning message) I don't understand, can anyone elaborate what this message means?

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There are many complex-valued solutions; Mathematica gives you the unique real-valued one here but warns you about the loss of generality. If you want all solutions, try

Reduce[1 == 125/2*E^(-30*10^6/x), x]
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    $\begingroup$ Or Solve[1 == 125/2*E^(-30*10^6/x), x, Method -> Reduce] $\endgroup$ – Bob Hanlon Jan 10 at 19:30
  • $\begingroup$ Thanks! Both methods work well. $\endgroup$ – baker Jan 14 at 13:33
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Tell Mathematica that you search for a real solution:

Solve[1 == 125/2*E^(-30*10^6/x), x, Reals]
(*{{x -> -(30000000/(Log[2] - 3 Log[5]))}}*)
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  • $\begingroup$ Thanks, I do only need reals, great suggestion. $\endgroup$ – baker Jan 14 at 13:35

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