Tan alfa-cotan alfa _________________ = Tan alfa+cotan alfa Tlong di jeb y

Ingat sifat dari trigonometri: [tex]sin^{2}\alpha+cos^{2}\alpha=1[/tex]
[tex]\frac{tan \alpha -cotan \alpha }{tan \alpha +cotan \alpha } [/tex]
=> [tex]\frac{\frac{sin\alpha}{cos\alpha}-\frac{1}{tan\alpha}}{\frac{sin\alpha}{cos\alpha}+\frac{1}{tan\alpha}}[/tex]
=> [tex]\frac{\frac{sin^{2}\alpha-cos^{2}\alpha}{sin\alpha cos\alpha}}{\frac{sin^{2}\alpha+cos^{2}\alpha}{sin\alpha cos\alpha}}[/tex]
=> [tex]\frac{sin^{2}\alpha-cos^{2}\alpha}{sin^{2}\alpha+cos^{2}\alpha}[/tex]
=> [tex]sin^{2}\alpha-cos^{2}\alpha[/tex]

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