I am trying to solve an equation using Mathematica, but I keep getting the following error

Solve::nsmet: This system cannot be solved with the methods available to Solve.

More importantly, it is running for more than half an hour without giving any solution. I have also tried Reduce, but that does not work either.

Any suggestions? How I can fix the error? I am new to Mathematica. My apologies if this is a very basic question.

I am trying to find θ1 (angle)?

x = (e*b*Cos[θ1] + v)^2/(v^2 + e^2*b^2 + 2*e*v*b*Cos[θ1])

Eq2 = a^2 + e*(Sin[θ]- Sin[θ1]) + v/b(θ-θ1)-a*Sqrt[x] == 
   a^2*x + e^2*(Cos[θ]-Cos[θ1])^2- 2*a*e*(Cos[θ]-Cos[θ1])*Sqrt[x]

Solve[Eq2, θ1]
  • $\begingroup$ inside the square bracket is theta just pls type in mathematica Theta rathar then 01 let you know ta $\endgroup$
    – polat
    Jan 31, 2013 at 5:15
  • 1
    $\begingroup$ Hello, and welcome to Mathematica.SE! Please take a look at the FAQ when posting. Regarding your comment, just know that you can still edit your question after it has been posted. Also, please try to block out your code (look at the editing help link.). $\endgroup$
    – VF1
    Jan 31, 2013 at 5:27
  • $\begingroup$ Your equation cannot be handled by Solve; you can use FindRoot to get a numerical solution once you specify a numerical value for the parameters. $\endgroup$ Jan 31, 2013 at 8:08
  • $\begingroup$ Thank you for your comment ,However when i used Find root i got this error.... the function value is not a list of numbers with dimensions...FindRoot[Eq2, θ1,Reals] or i wrote [Eq2, θ1,-Pi,Pi] didnt work :(Could you pls help me how would you write the a numerical value for the paremeters Thank u $\endgroup$
    – polat
    Feb 1, 2013 at 4:29

1 Answer 1


Many classes of equations cannot be solved analytically. If you know the values of your parameters you could use a numerical approach:

Block[{e = 1, b = 2, v = 3, a = 4, θ = 5}, 
 FindRoot[Eq2, {θ1, 1}]

{θ1 -> 0.9082966746}


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.