Первое задание!!!!!!!!!!

Question

Первое задание!!!!!!!!!!

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Answer 1

Sin²α/(cosα-1)=-sin²α/(1-cosα)=-(1-cos²α)/(1-cosα)=
=-(1-cosα)(1+cosα)/(1-cosα)=-(1+cosα)=-1-cosα.  Ответ: 4).