Somehow Mathematica is not able to solve a function which involves a ''Which'' function. That is, the function is defined differently in different regions.
So a simple NSolve or a FindRoot should have worked.But it gives this warning
''Cannot use compiled code; Argument \!\(theta\) at position \!\(1\) \
should be a machine-size real number.''
''The expression \!\(Which[\(\(theta < \(-1.74532925199432948`\)\), \
\(\\[LeftSkeleton] 4 \\[RightSkeleton]\), \(\*StyleBox[\''20.`\'', \
Rule[PrintPrecision, 2], Rule[StyleBoxAutoDelete, True]]\\ \
\(Sin[theta]\)\)\)]\) involves unknowns in more than one argument, so inverse \
functions cannot be used.''
and does not solve the equation.
Is there any rule about the kind of equations Mathematica can solve?
Thanks a lot, I am very thankful for the advice which I get in this forum from time to time.