a). f(x) = cos(x-π/6)
f ' (x) = (cos(x-π/6)) ' = -sin(x-π/6)*(x-π/6) ' = -sin(x-π/6)*1 = -sin(x-π/6)
б). f(x) = sin(π/4 -x)
f '(x) = cos(π/4 -x)*(π/4 -x) ' = cos(π/4 -x)*(-1) = - cos(π/4 -x)
в). f(x)=ctg(π/6 +x)
f '(x) = -(1/sin²(π/6 + x))*(π/6 +x) ' = -(1/sin²(π/6 + x))*1 = -(1/sin²(π/6 + x))
г). f(x) = tg(x+π/3)
f '(x) = 1/cos²(x+π/3)*(x+π/3) ' = 1/cos²(x+π/3)*1 = 1/cos²(x+π/3)