Ребят, спасите :((((

Question

Ребят, спасите :((((

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Answer 1

Ctg (π/2 + 5α) · ctg (π – 5α) + (1 – cos²α) / (1 – sin²α) =
= – tg 5α · (– ctg 5α) + sin²α / cos²α =
= 1 + tg²α = 1 / cos²α