Mister Exam

Lang:

Graphing y = sqrt(5*x)-4

You have entered [src]

         _____    
f(x) = \/ 5*x  - 4

f{\left(x \right)} = \sqrt{5 x} - 4

f = sqrt(5*x) - 4

The graph of the function

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:

\sqrt{5 x} - 4 = 0

Solve this equation
The points of intersection with the axis X:

Analytical solution

x_{1} = \frac{16}{5}

Numerical solution

x_{1} = 3.2

The points of intersection with the Y axis coordinate

The graph crosses Y axis when x equals 0:
substitute x = 0 to sqrt(5*x) - 4.

-4 + \sqrt{0 \cdot 5}

The result:

f{\left(0 \right)} = -4

The point:

(0, -4)

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)} =

\frac{\sqrt{5} \sqrt{x}}{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)} =

- \frac{\sqrt{5}}{4 x^{\frac{3}{2}}} = 0

Solve this equation
Solutions are not found,
maybe, the function has no inflections

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(\sqrt{5 x} - 4\right) = \infty i

Let's take the limit
so,
horizontal asymptote on the left doesn’t exist

\lim_{x \to \infty}\left(\sqrt{5 x} - 4\right) = \infty

Let's take the limit
so,
horizontal asymptote on the right doesn’t exist

Inclined asymptotes

Inclined asymptote can be found by calculating the limit of sqrt(5*x) - 4, divided by x at x->+oo and x ->-oo

\lim_{x \to -\infty}\left(\frac{\sqrt{5 x} - 4}{x}\right) = 0

Let's take the limit
so,
inclined coincides with the horizontal asymptote on the right

\lim_{x \to \infty}\left(\frac{\sqrt{5 x} - 4}{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:

\sqrt{5 x} - 4 = \sqrt{5} \sqrt{- x} - 4

- No

\sqrt{5 x} - 4 = - \sqrt{5} \sqrt{- x} + 4

- No
so, the function
not is
neither even, nor odd