Çözüldü Trigonometrik Çember

https://i72.servimg.com/u/f72/19/97/10/39/trigo141.png
https://drive.google.com/file/d/1jCTu0khE87uizD6D3xrWeAb8-LY4xvmn/view
(Sayfa 30, Soru 40, Cevaplar Son Sayfada, Deneme Testi 2A)

sin(11π / 2 - α) = sin[ 5π + (π / 2 - α) ] = -sin(π / 2 - α) = -cos(α)....(I)
veya sin[ 5π + (π / 2 - α) ] = sin[ π / 2 + (5π - α) ] = cos(5π - α) = -cos(α)
cos(8π - α) = cos(α)....(II)
sin(7π - α) = sin(α)....(III)
cos(25π / 2 + α) = cos[ 12π + (π / 2 + α) ] = cos(π / 2 + α) = -sin(α)....(IV)
(I), (II), (III), (IV) eşitlikleriyle [ -cos(α) - cos(α) ] / { sin(α) - [ -sin(α) ] } = -cot(α).