Respuesta :

mhanifa

Answer:

  • - 1 - sin α

Step-by-step explanation:

Use identity:

  • sin² α + cos² α = 1 ⇒ cos² α = 1 - sin² α = (1 + sin α)(1 - sin α)

Substitute this into given expression and simplify:

  • cos² α / (sin α - 1) =
  • (1 + sin α)(1 - sin α) / (sin α - 1) =
  • - (1 + sin α) =
  • - 1 - sin α

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