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if f(x)=x^2+kx+1 is increasing function in the interval [1,2] then the least value of k is

if f(x)=x^2+kx+1 is increasing function in the interval [1,2] then the least value of k is
 

Grade:12th pass

1 Answers

Arun
25757 Points
4 years ago
 

Hi,

f(x) = x2 + kx + 1

f'(x) = 2x + k >= 0 if f(x) is increasing

Or,

k>= -2x

Now x ε (1,2)

thus,

k>= -2

 

Regards

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