find solution,sin,cos,tan

solve the following equation for0<x<360度
1.
0<=x<=360度
0<=2x<=720度
cos 2x = 0.4
2x=66.42度or 2x=293.58度or 2x=426.42度or 2x=653.58度
x=33.41度or x=146.7度9 or x=213.21度or x=326.79度
2.
2tan 3x =－4
0<=x<=360度
0<=3x<=1080度
2tan 3x =－4
tan 3x =－2
3x=116.565度or 3x=296.565度or 3x=476.565度or 3x=656.565度
or 3x=836.565度 or3x=1016.565度
x=38.855度or x=98.855度or x=158.855度or x=218.855度
orx=278.855度 or x=338.855度

cos 2x=0.4
2x=arccos 0.4=66.4218
x=33.2109

2 tan 3x=-4
tan 3x=-2
3x=-63.4350
x=-21.1450

2011-04-27 11:30:26 補充：
1)
x=
33.210910760899084447988750290086286318925187484918205460339905822855058552201037951969670552381940556968833576319317718526292996462957043955126797736397372734976862603512341972893889417096901529501549448481775011831499228213538772458656084361065161740316310610200100898417170623778059251441406

2011-04-27 11:31:06 補充：
2)
x=
-21.14498294097400354947593542651556844293192856678492632400466122823731139283841979609714206313261175956309786449523031098769126270872455036300853066952751240035887202749445344032300770645037581190437340394790744630919157900454849045476851270589882199708912960655089580510984348018474013182961