Problem with math_FunctionSetRoot and math_NewtonFunctionSetRoot

Is any one know what the alogrithm that math_FunctionSetRoot used, I found a lot of
problems when I use math_FunctionSetRoot and math_NewtonFunctionSetRoot,
Is there any solution?
attachment is the bug I found and the model I used.

SunHongLei's picture

the point i used is (0.7694,0.43602,0.0963475)