Matematika

Pertanyaan

cara mencari tan 52,5 (pake jalan cara nya ya)
mohon bantuanyaa,untuk besok

1 Jawaban

  • [tex]
    \text{Misalkan }\tan{52.5\degree}=x\\
    \text{Selanjutnya, perhatikan bahwa}\\
    \tan{105\degree}
    =\tan{(2\cdot52.5\degree)}\\
    =\frac{2\tan{52.5\degree}}{1-\tan^2{52.5\degree}}\\
    =\frac{2x}{1-x^2}\\
    \text{Sekarang, perhatikan bahwa}\\
    \tan{105\degree}\\
    =\tan{(90\degree+15\degree)}\\
    =-\cot{15\degree}\\
    =-\cot{(45\degree-30\degree)}\\
    =-\frac{1+\tan{45\degree}\cdot\tan{30\degree}}{\tan{45\degree}-\tan{30\degree}}\\
    =-\frac{1+1\cdot\frac{1}{\sqrt{3}}}{1-\frac{1}{\sqrt{3}}}\cdot\frac{\sqrt{3}}{\sqrt{3}}\\
    =-\frac{\sqrt{3}+1}{\sqrt{3}-1}\\
    \text{Dengan demikian, diperoleh kesamaan}\\
    -\frac{\sqrt{3}+1}{\sqrt{3}-1}=\frac{2x}{1-x^2}\\
    \Leftrightarrow-\sqrt{3}-1+(\sqrt{3}+1)x^2=2(\sqrt{3}-1)x\\
    \Leftrightarrow(\sqrt{3}+1)x^2-2(\sqrt{3}-1)x-\sqrt{3}-1=0\\
    \text{well, dengan menggunakan rumus kuadrat (dan sedikit kesabaran) akan diperoleh}\\
    x = \tan{52.5\degree}=\frac{-1+\sqrt{3}+\sqrt{20+6\sqrt{3}}}{2(1+\sqrt{3})}\\
    [/tex]

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