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1-1-cos-2-x-1-sin-2-x-1-48-35-




Question Number 169771 by greougoury555 last updated on 08/May/22
      (1/(1+cos^2 x)) + (1/(sin^2 x+1)) = ((48)/(35))
$$\:\:\:\:\:\:\frac{\mathrm{1}}{\mathrm{1}+\mathrm{cos}\:^{\mathrm{2}} {x}}\:+\:\frac{\mathrm{1}}{\mathrm{sin}\:^{\mathrm{2}} {x}+\mathrm{1}}\:=\:\frac{\mathrm{48}}{\mathrm{35}} \\ $$
Answered by kapoorshah last updated on 08/May/22
SyberMath
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Answered by thfchristopher last updated on 08/May/22
⇒((1+sin^2 x+1+cos^2 x)/(1+sin^2 x+sin^2 xcos^2 x+cos^2 x))=((48)/(35))  ⇒(3/(2+sin^2 xcos^2 x))=((48)/(35))  ⇒105=96+48sin^2 xcos^2 x  ⇒sin^2 xcos^2 x=(9/(48))  ⇒(1/4)sin^2 2x=(9/(48))  ⇒sin^2 2x=((36)/(48))  ⇒sin 2x=((√3)/2)     or    sin 2x=−((√3)/2)  2x=nπ∓(π/3)  x=((nπ)/2)∓(π/6)
$$\Rightarrow\frac{\mathrm{1}+\mathrm{sin}^{\mathrm{2}} {x}+\mathrm{1}+\mathrm{cos}^{\mathrm{2}} {x}}{\mathrm{1}+\mathrm{sin}^{\mathrm{2}} {x}+\mathrm{sin}^{\mathrm{2}} {x}\mathrm{cos}^{\mathrm{2}} {x}+\mathrm{cos}^{\mathrm{2}} {x}}=\frac{\mathrm{48}}{\mathrm{35}} \\ $$$$\Rightarrow\frac{\mathrm{3}}{\mathrm{2}+\mathrm{sin}^{\mathrm{2}} {x}\mathrm{cos}^{\mathrm{2}} {x}}=\frac{\mathrm{48}}{\mathrm{35}} \\ $$$$\Rightarrow\mathrm{105}=\mathrm{96}+\mathrm{48sin}^{\mathrm{2}} {x}\mathrm{cos}^{\mathrm{2}} {x} \\ $$$$\Rightarrow\mathrm{sin}^{\mathrm{2}} {x}\mathrm{cos}^{\mathrm{2}} {x}=\frac{\mathrm{9}}{\mathrm{48}} \\ $$$$\Rightarrow\frac{\mathrm{1}}{\mathrm{4}}\mathrm{sin}^{\mathrm{2}} \mathrm{2}{x}=\frac{\mathrm{9}}{\mathrm{48}} \\ $$$$\Rightarrow\mathrm{sin}^{\mathrm{2}} \mathrm{2}{x}=\frac{\mathrm{36}}{\mathrm{48}} \\ $$$$\Rightarrow\mathrm{sin}\:\mathrm{2}{x}=\frac{\sqrt{\mathrm{3}}}{\mathrm{2}}\:\:\:\:\:\mathrm{or}\:\:\:\:\mathrm{sin}\:\mathrm{2}{x}=−\frac{\sqrt{\mathrm{3}}}{\mathrm{2}} \\ $$$$\mathrm{2}{x}={n}\pi\mp\frac{\pi}{\mathrm{3}} \\ $$$${x}=\frac{{n}\pi}{\mathrm{2}}\mp\frac{\pi}{\mathrm{6}} \\ $$
Answered by cortano1 last updated on 08/May/22

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