cos^2(-π/12) = cos^2(π/12)
Поскольку cos(π/12) = cos(-π/12), то cos^2(-π/12) = cos^2(π/12)
Таким образом, cos^2(-π/12) = cos^2(π/12)
cos^2(-π/12) = cos^2(π/12)
Поскольку cos(π/12) = cos(-π/12), то cos^2(-π/12) = cos^2(π/12)
Таким образом, cos^2(-π/12) = cos^2(π/12)