已知函數(shù)f(x)=mx^3-3(m+1)x^2+(3m+6)x+1,(m
已知函數(shù)f(x)=mx^3-3(m+1)x^2+(3m+6)x+1,(m<0),
當(dāng)x∈【-1,1】時(shí),函數(shù)y=f(x)的圖像上任一點(diǎn)的切線大于3m,求m的范圍
優(yōu)質(zhì)解答
求導(dǎo)數(shù)
3mx^2-6(m+1)x+3m+6>3m
3mx^2-6(m+1)x+6>0
不論m取什么范圍,函數(shù)必須與x軸有交點(diǎn)
[6(m+1)}^2-4*3m*6>0
m^2+2m+1>0
5-2根號(hào)6