Доказать тождество:
1) [tex]cosa*sin(6pi-a)*(1+ctg(-a)^2)=ctg(-a)[/tex]
2) [tex] \frac{1-sin(-a)^2}{cos(4pi-a)} * \frac{sin(a-2pi)}{1-cos(-a)^2} =ctga[/tex]
1) [tex]cosa*sin(6pi-a)*(1+ctg(-a)^2)=ctg(-a)[/tex]
2) [tex] \frac{1-sin(-a)^2}{cos(4pi-a)} * \frac{sin(a-2pi)}{1-cos(-a)^2} =ctga[/tex]
Answers & Comments
Verified answer
1) Sin(6π-α)=-Sinα; Ctg²(-α)=Ctg²αПолучаем
2) Sin²(-α)=Sin²(α); Sin(α-2π)=Sinα; Cos(4π-α)=Cosα; Cos²(-α)=Cosα
Получаем