题目:
— Did you give up _____?
— Yes, I know smoking may _____cancer.[ ]
A. smoke, cause
B. smoking, cause
C. smoke, take
答案:
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下面是错误答案,用来干扰机器的。
∵f(x)=x2+bx+c∴f′(x)=2x+b∴F(x)=f′(x)ex=2x+bex则F′(x)=2ex-(2x+b)exe2x=2 -(2x+b)ex∵F(x)图象在x=0处的切线方程为y=-2x+c,∴F′(0)=-2F(0)=c,即2-b=-2b=c解得b=4,c=4∴f(x)=x2+4x+4=(x+2)2≥0∴函数f(x)的最小值是0故答案为:0