menghilangkan theta antara a=cos(theta-alpha) dan b=sin(theta-beta)

ta – Alpha = cos^-1(a) (equ.1)
ta – Beta = sin^-1(b) (equ.2)
Mengurangi persamaan, kita mendapatkan
Beta – Alpha = cos^-1(a) – sin^-1(b)

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