(1)tanx=-2 π/20sinx=-2/根号(5) cosx=1/根号(5)sinx-cosx=-3/根号(5)(2)sin(360-x)cos(180-x)-sinx2/cos(180+x)cos(90-x)+cos^2x=-sinx*(-cosx)-2sinx*cosx/((-cosx)*sinx)+cos^2x=sinx*cosx+2+cos2x/2+1/2=sin2x*/2+2+cos2x/2+1/2=根号(2)sin(2x+pi/4)+5/2