<span>4+ctg^2x=4+ cos^2x/sin^2x=4+(1-sin^2x)/sin^2x=4+ (1-0,2)/0,2=4+0,8/0,2=4+4=8</span>
у'=(х²/2)' =1/2(х²)'= 1/2 *2х =х
Y`(x)=(3x²*(3-x²-3x)-x³*(-2x-3))/(3-x²-3x)²=(9x²-3x^4-9x³+2x^4+3x³)/(3-x²-3x)²=
(-x^4-6x³+9x²)/(3-x²-3x)²=x²(9-6x-x²)/(3-x²-3x)²=0
x²(9-6x-x²)=0
x=0
9-6x-x²=0
D=36+36=72 √D=6√2
x1=(6-6√2)/-2=3√2-3
x2=(6+6√2)/-2=-3√2-3
D = (-1)2 - 4 • 1 • (-2) = 9