Y=46sinx-46x+p/4. найти наименьшее значение функции на отрезке [-p/2; p/2}

Y=46sinx-46x+π/4
y`=46cosx-46
46cosx-46=0
46cosx=46
cosx=1
x=2πn
n=0  x=0∈[-π/2;π/2]
y(-π/2)=46sin(-π/2)-46*(-π/2)+π/4=-46+23π+π/4≈27 наиб
y(0)=46sin0-46*0+π/4=π/4≈0,8
y(π/2)=46sinπ/2-46*π/2+π/4=46-23π+π/4≈-25,4 наим