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Mathematics Calculus Equation Solving Wolfram Language

Solve trig equations with unknowns both in and out trig functions?

Posted 5 years ago

Good morning everyone, I'm new to the forum and a Wolfram beginner. I'm having troubles calculating trigonometric functions with unknowns both in and out of the brackets of trigonometric functions eg: `Cos[x] - x Sin[x]==0` I usually use Solve for polynomial equations, but neither Solve not Reduce can face these kind of problems Can someone please help me? Thank You

POSTED BY: Claudia Zara

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Posted 5 years ago

Thank you very much to both of you for your answers, they will be precious.

POSTED BY: Claudia Zara

Posted 5 years ago

A little more than the problem you are trying to solve: http://mathworld.wolfram.com/TancFunction.html If you follow the SE article carefully, you will have a very nice conclusion (though you have Cotc, the argument is the same) https://math.stackexchange.com/a/451723/111285 Therefore, you have a numerically robust way to find nth solution when `n` is very large: In[1]:= n=100; In[2]:= FindRoot[Cot[x]==x,{x,n\[Pi]+1/(n\[Pi])}] Out[2]= {x->314.162} A notebooks is attached for you to play around. Attachments: solution.nb