Question:
The function $f(x)=\frac{x}{2}+\frac{2}{x}$ has a local minimum at $x=$________________
Solution:
The given function is $f(x)=\frac{x}{2}+\frac{2}{x}, x \neq 0$.
$f(x)=\frac{x}{2}+\frac{2}{x}$
Differentiating both sides with respect to x, we get
$f^{\prime}(x)=\frac{1}{2}-\frac{2}{x^{2}}$
For maxima or minima,
$f^{\prime}(x)=0$
At x = −2, we have
$f^{\prime \prime}(-2)=\frac{4}{(-2)^{3}}=-\frac{1}{2}<0$
So, $x=-2$ is the point of local maximum of $f(x)$.
At x = 2, we have
$f^{\prime \prime}(2)=\frac{4}{(2)^{3}}=\frac{1}{2}>0$
So, x = 2 is the point of local minimum of f(x).
Thus, the given function $f(x)=\frac{x}{2}+\frac{2}{x}$ has a local minimum at $x=2$
The function $f(x)=\frac{x}{2}+\frac{2}{x}$ has a local minimum at $x=$ ____2____.