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It is given that...

發問:

It is given that tanx=(1+cosx)/2sinx. a)Show that 3cos^2x+cosx-2=0. b)Hence,solve tanx=(1+cosx)/2sinx for 0°<=x<=360°. (Given your answers correct to 1 decimal place if necessary.)

最佳解答:

a) tanx=(1+cosx)/2sinx sinx/cosx=(1+cosx)/2sinx 2sin2x=cosx(1+cosx) 2(1-cos2x)= cosx+cos2x 2-2cos2x= cosx+cos2x 3cos2x+cosx-2=0 b) tanx=(1+cosx)/2sinx 3cos2x+cosx-2=0 (3cosx-2)(cosx+1)=0 cosx=2/3 or cosx=-1 x=48.2 o,180o or 311.8 o

其他解答:FAD2A23AB937987B
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