Y'= -2sinx+1
-2sinx+1=0
-2sinx=-1
sinx=1/2
x=(-1)ⁿ π/6 + πn, n∈Z
При n=0 x=(-1)⁰ * π/6 + π*0= π/6
y(-π/2)=2cos(-π/2)- π/2 = 2*0 - π/2= -π/2 - наименьшее
y(π/6)=2cos(π/6)+ π/6 = 2 * (√3/2) + π/6= √3 + π/6 ≈ 2,255 - наибольшее
y(π/2)=2cos(π/2) + π/2 = 2*0 + π/2 = π/2 ≈ 1,57