<span>(9-b)^2 - b(b-7) = 81 - 18b +b^2 - b^2 +7b = 81 - 11b = 81 - 11*(-0,8)= 81+ 8,8 = 89,8.</span>
X=-3π/2 y=4sinx-5cosx+11x-10 y=-4sin3π/2-5cos3π/2-11*3π/2-10=
=4-33π/2-10=-6-33π/2
x=0 y=-5-33π/2-10=-15-33π/2
y'=4cosx+5sinx+11=0
4cosx+5sinx=-11 4cosx+5sinx>-9 решений нет.
наибольшее значение -6-33π/2
-0,8*(-5/6) - 11/12 = 0,8*(5/6) - 11/12 = 4/6 - 11/12 = 8/12 - 11/12 = -3/12 = -1/4 = -0,25