当x为何实数时,y=x^2-x+1+[2(x+3)^2+2(x^2-5)^2]^0.5有最小值,最小值为多少?可否说详细点,

问题描述:

当x为何实数时,y=x^2-x+1+[2(x+3)^2+2(x^2-5)^2]^0.5有最小值,最小值为多少?可否说详细点,

f'(x)=2x-1+0.5(4(x+3)+4(x^2-5)(2x))/[2(x+3)^2+2(x^2-5)^2]^0.5 =2x-1+2(x+3+2x^3-10x)/[2(x+3)^2+2(x^2-5)^2]^0.5 =2x-1+2(2x^3-9x+3)/[2(x+3)^2+2(x^2-5)^2]^0.5[2(x+3)^2+2(x^2-5)^2]^0.5,只在x=-3且x=...