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设函数f(x)=ax+1/(x+b)(a.b∈z),曲线y=f(x)在点(2,f(2))处的切线方程式为y=3,
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f'(x)=a-1/(x+b)^2
So f'(2)=a-1/(b+2)^2=0
Then we have:
a*(b+2)^2=1
Also, we know f(2)=3
that is:2*a+1/(b+2)=3
then 2/(b+2)^2+1/(b+2)-3=0
Solve the eq.,we have:b=-1,or b=-8/3
.........
........
So f'(2)=a-1/(b+2)^2=0
Then we have:
a*(b+2)^2=1
Also, we know f(2)=3
that is:2*a+1/(b+2)=3
then 2/(b+2)^2+1/(b+2)-3=0
Solve the eq.,we have:b=-1,or b=-8/3
.........
........
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