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The equation `sin^4x+cos^4x+sin2x+alpha=0`is solvable for`-5/2lt=alphalt=1/2`(b) `-3lt=alpha |
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Answer» `sin^4x+cos^4x+sin2x+alpha=0` `(sin^2x)^2+(cos^2x)^2+sin2x+alpha=0` `(sinn^2x+cos^2x)^2-2sin^2x*cos^2x+sin2x+alpha=0` `1-2sin^2x*cos^2x+sin2x+alpha=0` `1-2(sin^2 2x)/4+sin2x+alpha=0` `2-sin^2 2alpha+2sin2x+2alpha=0` `2alpha=sin^2 2alpha-2sin2x-2` `2alpha=y^2-2y-2` `2alpha=(y-1)^2-3` `alpha=(y-1)^2/2-3/2` `-1<=y<=1` `-2<=y-1<=0` `0<=(y-1)^2<=4` `-3<=(y-1)^2-3<=1` `-3<=2alpha<=1` `-3/2<=alpha<=1/2`. |
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