已知tanx=2010,则[1-sin(9π/2-2x)]/sin(9π-2x)=答案是2010.,但我算出来是1/2010

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已知tanx=2010,则[1-sin(9π/2-2x)]/sin(9π-2x)=答案是2010.,但我算出来是1/2010

已知tanx=2010,则[1-sin(9π/2-2x)]/sin(9π-2x)=答案是2010.,但我算出来是1/2010
已知tanx=2010,则[1-sin(9π/2-2x)]/sin(9π-2x)=
答案是2010.,但我算出来是1/2010

已知tanx=2010,则[1-sin(9π/2-2x)]/sin(9π-2x)=答案是2010.,但我算出来是1/2010
原式=(1-cos2x)/sin2x
=[1-(1-2sin²x)]/2sinxcosx
=2sin²x/2sinxcosx
=sinx/cosx
=tanx
=2010

是2010 分子化简得(1-cos2x),即2sinx*sinx,分母得sin2x,即2sinx*cosx,约分得tanx=2010