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 Author Comment/Response jf 03/13/13 12:42pm Solve is happiest with polynomials. For a complicated equation, a numerical solver like FindRoot is more likely to work. In[1]:= f[x__]:=(Sqrt[2] Sqrt[-E^(-2 p x) g R (-2-14 p^2-E^(2 p x) Cos[x]+2 E^(2 p x) p^2 Cos[x]+3 E^(2 p x) p Sin[x])])/Sqrt[1+4 p^2] In[2]:= g=10; R=2; p=0.3; In[5]:= FindRoot[ f[x]^2==-g R Cos[x], {x,1}] Out[5]= {x->1.74393} This takes the Rule that FindRoot gives and uses it to substitute the value for the x's: In[6]:= f[x]^2==-g R Cos[x] /. % Out[6]= True FindRoot is included in the See Also in the reference page for Solve and in http://reference.wolfram.com/mathematica/tutorial/SolvingEquations.html URL: ,

 Subject (listing for 'I want to approximate a root of this equation') Author Date Posted I want to approximate a root of this equation Joćo Maldonado 03/13/13 12:04pm Re: I want to approximate a root of this equation jf 03/13/13 12:42pm
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