Mister Exam

Graphing y = log(6-4*x)

v

The graph:

from to

Intersection points:

does show?

Piecewise:

The solution

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f(x) = log(6 - 4*x)
f(x)=log(64x)f{\left(x \right)} = \log{\left(6 - 4 x \right)}
f = log(6 - 4*x)
The graph of the function
02468-8-6-4-2-10105-5
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:
log(64x)=0\log{\left(6 - 4 x \right)} = 0
Solve this equation
The points of intersection with the axis X:

Analytical solution
x1=54x_{1} = \frac{5}{4}
Numerical solution
x1=1.25x_{1} = 1.25
The points of intersection with the Y axis coordinate
The graph crosses Y axis when x equals 0:
substitute x = 0 to log(6 - 4*x).
log(60)\log{\left(6 - 0 \right)}
The result:
f(0)=log(6)f{\left(0 \right)} = \log{\left(6 \right)}
The point:
(0, log(6))
Extrema of the function
In order to find the extrema, we need to solve the equation
ddxf(x)=0\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:
ddxf(x)=\frac{d}{d x} f{\left(x \right)} =
the first derivative
464x=0- \frac{4}{6 - 4 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
d2dx2f(x)=0\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:
d2dx2f(x)=\frac{d^{2}}{d x^{2}} f{\left(x \right)} =
the second derivative
4(2x3)2=0- \frac{4}{\left(2 x - 3\right)^{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
limxlog(64x)=\lim_{x \to -\infty} \log{\left(6 - 4 x \right)} = \infty
Let's take the limit
so,
horizontal asymptote on the left doesn’t exist
limxlog(64x)=\lim_{x \to \infty} \log{\left(6 - 4 x \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 log(6 - 4*x), divided by x at x->+oo and x ->-oo
limx(log(64x)x)=0\lim_{x \to -\infty}\left(\frac{\log{\left(6 - 4 x \right)}}{x}\right) = 0
Let's take the limit
so,
inclined coincides with the horizontal asymptote on the right
limx(log(64x)x)=0\lim_{x \to \infty}\left(\frac{\log{\left(6 - 4 x \right)}}{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:
log(64x)=log(4x+6)\log{\left(6 - 4 x \right)} = \log{\left(4 x + 6 \right)}
- No
log(64x)=log(4x+6)\log{\left(6 - 4 x \right)} = - \log{\left(4 x + 6 \right)}
- No
so, the function
not is
neither even, nor odd