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標題:

a.maths

發問:

solve for 0
最佳解答:

a.maths solve for 0
其他解答:

(1-tanx)(1+sin2x)=1+tanx 1 - sinx/cosx + 2sinxcosx - 2sin^2 x = 1+ sinx/cosx 2sinx cosx - 2sin^2 x - 2sinx/cosx = 0 sinx = 0.......................or ........................ 2cosx - 2sinx - 2/cosx = 0 x= 180 or 360...........................................cos^2 x - sinxcosx -1 = 0 ...............................................................sinxcosx + 1 - cos^2 x=0 ...............................................................sinxcos +sin^2 x = 0 ............................................................sinx=0.............or............cosx+sinx=0 ...........................................................(repeated)...................sin(90-x)+sinx=0 .........................................................................................2sin45cos(45-x)=0 ..................................................................................................cos(x-45)=0 .............................................................................................x-45=90, 270 .................................................................................................x=135, 315 i.e. overall solution is x=135,180,315,360 2007-02-20 23:40:42 補充： i am overlooking the question,360 is not the required answer,if you want, the general solutin isx=n(pi)............. or.................2n(pi) 3(pi)/4..........or .............2n(pi)-(pi)/4where n is any integers|||||(1-tanx)(1+sin2x)=1+tanx 1-sin2xtanx-tanx+sin2x-1-tanx=0 2sinxcosx-2sinxcosx(sinx/cosx)-sinxcosx=0 2sinxcos^2x-2sin^2x-sinxcos^2x=0 2sinx(1-sin^2x)-2sin^2x-sinx(1-sin^2x)=0 2sinx-2sin^3x-2sin^2x-sinx+sin^3x=0 sin^3x+2sin^2x-sinx=0 sinx(sin^2x+2sinx-1)=0 sinx=0 or sinx=[-2+/-(8)^0.5]/2 x=0,180,360 or x=24.47 , sinx=-2.414(rejected) (corr. to 4 sig. fig.) 2007-02-20 22:42:29 補充： sorry, x=/=360 2007-02-21 00:43:05 補充： 2sinxcosx-2sinxcosx(sinx/cosx)-sinxcosx=0呢一步做錯左．．．．A9A39959EDCC7BE3