Question

Решите!!! Подробно. Тригонометрия

Answer 1

(1+sin²α)*ctg²α-1/sin²α=ctg²α+sin²α*ctg²α-1/sin²α=cos²α/sin²α=sin²α*(cos²α/sin²α)-1/sin²α=cos²α/sin²α-1/sin²α+cos²α=(cos²α-1)/sin²α+cos²α=-sin²α/sin²α+cos²α=-1+cos²α=-sin²α