Mister Exam
Graphing y = 1/(x/9)-x/(2*x)
The solution
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1 x
f(x) = --- - ---
/x\ 2*x
|-|
\9/
$$f{\left(x \right)} = - \frac{x}{2 x} + \frac{1}{\frac{1}{9} x}$$
f = -x/(2*x) + 1/(x/9)
The graph of the function
The domain of the function
The points at which the function is not precisely defined:
$$x_{1} = 0$$
$$x_{1} = 0$$
The points of intersection with the X-axis coordinate
Graph of the function intersects the axis X at f = 0
so we need to solve the equation:
$$- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x} = 0$$
Solve this equation
The points of intersection with the axis X:
Analytical solution
$$x_{1} = 18$$
Numerical solution
$$x_{1} = 18$$
so we need to solve the equation:
$$- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x} = 0$$
Solve this equation
The points of intersection with the axis X:
Analytical solution
$$x_{1} = 18$$
Numerical solution
$$x_{1} = 18$$
Extrema of the function
In order to find the extrema, we need to solve the equation
$$\frac{d}{d x} f{\left(x \right)} = 0$$
(the derivative equals zero),
and the roots of this equation are the extrema of this function:
$$\frac{d}{d x} f{\left(x \right)} = $$
the first derivative
$$- \frac{9 \frac{1}{x}}{x} - \frac{1}{2 x} + \frac{1}{2 x} = 0$$
Solve this equation
Solutions are not found,
function may have no extrema
$$\frac{d}{d x} f{\left(x \right)} = 0$$
(the derivative equals zero),
and the roots of this equation are the extrema of this function:
$$\frac{d}{d x} f{\left(x \right)} = $$
the first derivative
$$- \frac{9 \frac{1}{x}}{x} - \frac{1}{2 x} + \frac{1}{2 x} = 0$$
Solve this equation
Solutions are not found,
function may have no extrema
Inflection points
Let's find the inflection points, we'll need to solve the equation for this
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0$$
(the second derivative equals zero),
the roots of this equation will be the inflection points for the specified function graph:
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = $$
the second derivative
$$\frac{18}{x^{3}} = 0$$
Solve this equation
Solutions are not found,
maybe, the function has no inflections
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0$$
(the second derivative equals zero),
the roots of this equation will be the inflection points for the specified function graph:
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = $$
the second derivative
$$\frac{18}{x^{3}} = 0$$
Solve this equation
Solutions are not found,
maybe, the function has no inflections
Vertical asymptotes
Have:
$$x_{1} = 0$$
$$x_{1} = 0$$
Horizontal asymptotes
Let’s find horizontal asymptotes with help of the limits of this function at x->+oo and x->-oo
$$\lim_{x \to -\infty}\left(- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x}\right) = - \frac{1}{2}$$
Let's take the limit
so,
equation of the horizontal asymptote on the left:
$$y = - \frac{1}{2}$$
$$\lim_{x \to \infty}\left(- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x}\right) = - \frac{1}{2}$$
Let's take the limit
so,
equation of the horizontal asymptote on the right:
$$y = - \frac{1}{2}$$
$$\lim_{x \to -\infty}\left(- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x}\right) = - \frac{1}{2}$$
Let's take the limit
so,
equation of the horizontal asymptote on the left:
$$y = - \frac{1}{2}$$
$$\lim_{x \to \infty}\left(- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x}\right) = - \frac{1}{2}$$
Let's take the limit
so,
equation of the horizontal asymptote on the right:
$$y = - \frac{1}{2}$$
Inclined asymptotes
Inclined asymptote can be found by calculating the limit of 1/(x/9) - x/(2*x), divided by x at x->+oo and x ->-oo
$$\lim_{x \to -\infty}\left(\frac{- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x}}{x}\right) = 0$$
Let's take the limit
so,
inclined coincides with the horizontal asymptote on the right
$$\lim_{x \to \infty}\left(\frac{- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x}}{x}\right) = 0$$
Let's take the limit
so,
inclined coincides with the horizontal asymptote on the left
$$\lim_{x \to -\infty}\left(\frac{- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x}}{x}\right) = 0$$
Let's take the limit
so,
inclined coincides with the horizontal asymptote on the right
$$\lim_{x \to \infty}\left(\frac{- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x}}{x}\right) = 0$$
Let's take the limit
so,
inclined coincides with the horizontal asymptote on the left
Even and odd functions
Let's check, whether the function even or odd by using relations f = f(-x) и f = -f(-x).
So, check:
$$- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x} = - \frac{1}{2} - \frac{9}{x}$$
- No
$$- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x} = \frac{1}{2} + \frac{9}{x}$$
- No
so, the function
not is
neither even, nor odd
So, check:
$$- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x} = - \frac{1}{2} - \frac{9}{x}$$
- No
$$- \frac{x}{2 x} + \frac{1}{\frac{1}{9} x} = \frac{1}{2} + \frac{9}{x}$$
- No
so, the function
not is
neither even, nor odd