Question

Find f such that the given conditions are satisfiedf’(x)=x-4, f(2)=-1

Answer 1

Given:

$f^{\prime}\left(x\right)=x-4,\text{ and}f\left(2\right)=-1$

To find:

The correct function.

Explanation:

Let us consider the function given in option D.

$f(x)=\frac{x^2}{2}-4x+5$

Differentiating with respect to x we get,

$\begin{gathered} f^{\prime}(x)=\frac{2x}{2}-4 \\ f^{\prime}(x)=x-4 \end{gathered}$

Substituting x = 2 in the function f(x), we get

$\begin{gathered} f(2)=\frac{2^2}{2}-4(2)+5 \\ =2-8+5 \\ =-6+5 \\ f(2)=-1 \end{gathered}$

Therefore, the given conditions are satisfied.

So, the function is,

$f(x)=\frac{x^{2}}{2}-4x+5$

Final answer: Option D