导数应用 急 (13 10:56:49)设f(x)=(1/3)X3 +aX2 +5X在区间『1,3』上为单调函数,则实数a的取值范围为( )
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![导数应用 急 (13 10:56:49)设f(x)=(1/3)X3 +aX2 +5X在区间『1,3』上为单调函数,则实数a的取值范围为( )](/uploads/image/z/1856312-8-2.jpg?t=%E5%AF%BC%E6%95%B0%E5%BA%94%E7%94%A8+%E6%80%A5+%2813+10%3A56%3A49%29%E8%AE%BEf%28x%29%3D%EF%BC%881%2F3%EF%BC%89X3+%2BaX2+%2B5X%E5%9C%A8%E5%8C%BA%E9%97%B4%E3%80%8E1%2C3%E3%80%8F%E4%B8%8A%E4%B8%BA%E5%8D%95%E8%B0%83%E5%87%BD%E6%95%B0%2C%E5%88%99%E5%AE%9E%E6%95%B0a%E7%9A%84%E5%8F%96%E5%80%BC%E8%8C%83%E5%9B%B4%E4%B8%BA%EF%BC%88%26%23160%3B%26%23160%3B%26%23160%3B%26%23160%3B%26%23160%3B%26%23160%3B+%29)
导数应用 急 (13 10:56:49)设f(x)=(1/3)X3 +aX2 +5X在区间『1,3』上为单调函数,则实数a的取值范围为( )
导数应用 急 (13 10:56:49)
设f(x)=(1/3)X3 +aX2 +5X在区间『1,3』上为单调函数,则实数a的取值范围为( )
导数应用 急 (13 10:56:49)设f(x)=(1/3)X3 +aX2 +5X在区间『1,3』上为单调函数,则实数a的取值范围为( )
f'=df(x)/dx=x^2+2ax+5
x=-a
1.-a<=1,a>=-1,f'(1)=1+2a+5=2a+6>=0,a>=-3,a>=-1,f'(3)=9+6a+5=6a+14<=0,a<=-7/3,kongji,a>=-1
2.-a>=3,a<=-3,f'(3)=6a+14>=0,a>=-7/3,kongji
f'(1)=2a+6<=0,a<=-3,
zongshang,a>=-1,a<=-3
thdtyu6t7u86786
“f(x)=(1/3)X3 +aX2 +5X”什么意思?
是三分之一X立方加a倍X平方加5倍X?是的话
f'=df(x)/dx=x^2+2ax+5
x=-a
1.-a<=1,a>=-1,f'(1)=1+2a+5=2a+6>=0,a>=-3,a>=-1,f'(3)=9+6a+5=6a+14<=0,a<=-7/3,kongji,a>=-1
2.-a>=3,a<=-3,f'(3)=6a+14>=0,a>=-7/3,kongji
f'(1)=2a+6<=0,a<=-3,
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f'=df(x)/dx=x^2+2ax+5
x=-a
1.-a<=1,a>=-1,f'(1)=1+2a+5=2a+6>=0,a>=-3,a>=-1,f'(3)=9+6a+5=6a+14<=0,a<=-7/3,kongji,a>=-1
2.-a>=3,a<=-3,f'(3)=6a+14>=0,a>=-7/3,kongji
f'(1)=2a+6<=0,a<=-3,
zongshang,a>=-1,a<=-3
“f(x)=(1/3)X3 +aX2 +5X”什么意思?
是三分之一X立方加a倍X平方加5倍X?是的话
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