f'=(x+2)(x-1)^2*(5x+4)驻点为-2,-4/5, 1,由f'符号得,极大值为胡返棚裤则f(-2). 极世型小值为f(-4/5).
F(x=)f(x)-1=(x+2)^2(x-1)^3F'(x)=2(x+2)(x-1)^3+3(x-1)^2(x+2))^2=(x+2)(x-1)^2(2(x-1)+3(x+2))=(x-1)((x+2)^2(5x+4)
fx=2x平方+x-1x=2f