If $f:[1,2] \rightarrow \mathbb{R}$ defined by $f(x)=x^2+2 k x+k$ is always negative then the interval in…

If $f:[1,2] \rightarrow \mathbb{R}$ defined by $f(x)=x^2+2 k x+k$ is always negative then the interval in which $k$ lies is
  1. $\left(\frac{4}{5}, \infty\right)$
  2. $\left(-\infty,-\frac{4}{5}\right)$
  3. $\left(-\infty, \frac{4}{5}\right)$
  4. $\left(-\frac{4}{5}, \infty\right)$

Solution

No solution. Refer to answer key.

Asked in: AP EAMCET 2017 (26 Apr Shift 2)

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