Помогите срочно!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Question

Помогите срочно!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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Answer 1

4) ctg a= cos a/sin a= 1/2
sin a= 2 cos a
получим :
10 cos a - 2 cos a / 2 cos a +10 cos a= 8/12=2/3

без 5 и 6

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