The points at which the function is not precisely defined: x1=4
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: x−4x+log(x)=0 Solve this equation The points of intersection with the axis X:
The points of intersection with the Y axis coordinate
The graph crosses Y axis when x equals 0: substitute x = 0 to (x + log(x))/(x - 4). −4log(0) The result: f(0)=∞~ sof doesn't intersect Y
Extrema of the function
In order to find the extrema, we need to solve the equation dxdf(x)=0 (the derivative equals zero), and the roots of this equation are the extrema of this function: dxdf(x)= the first derivative x−41+x1−(x−4)2x+log(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 dx2d2f(x)=0 (the second derivative equals zero), the roots of this equation will be the inflection points for the specified function graph: dx2d2f(x)= the second derivative x−4−x−42(1+x1)+(x−4)22(x+log(x))−x21=0 Solve this equation The roots of this equation x1=38783.8985529685 x2=45808.020325951 x3=29719.8418978506 x4=37778.7731403642 x5=31737.8127530236 x6=40792.827428034 x7=30729.1207207176 x8=0.8114375561742 x9=47811.4762989485 x10=46809.925612916 x11=34760.5793720106 x12=28709.9529706705 x13=35767.1290742184 x14=48812.6813980915 x15=44805.7509925326 x16=42800.0800645983 x17=43803.1077057361 x18=41796.6571384727 x19=32745.9397987124 x20=36773.1883391132 x21=27699.4289684316 x22=33753.5222833995 x23=39788.5788225481 You also need to calculate the limits of y '' for arguments seeking to indeterminate points of a function: Points where there is an indetermination: x1=4
x→4−limx−4−x−42(1+x1)+(x−4)22(x+log(x))−x21=−∞ x→4+limx−4−x−42(1+x1)+(x−4)22(x+log(x))−x21=∞ - the limits are not equal, so x1=4 - is an inflection point
Сonvexity and concavity intervals: Let’s find the intervals where the function is convex or concave, for this look at the behaviour of the function at the inflection points: Concave at the intervals (−∞,0.8114375561742] Convex at the intervals [0.8114375561742,∞)
Vertical asymptotes
Have: x1=4
Horizontal asymptotes
Let’s find horizontal asymptotes with help of the limits of this function at x->+oo and x->-oo x→−∞lim(x−4x+log(x))=1 Let's take the limit so, equation of the horizontal asymptote on the left: y=1 x→∞lim(x−4x+log(x))=1 Let's take the limit so, equation of the horizontal asymptote on the right: y=1
Inclined asymptotes
Inclined asymptote can be found by calculating the limit of (x + log(x))/(x - 4), divided by x at x->+oo and x ->-oo x→−∞lim(x(x−4)x+log(x))=0 Let's take the limit so, inclined coincides with the horizontal asymptote on the right x→∞lim(x(x−4)x+log(x))=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: x−4x+log(x)=−x−4−x+log(−x) - No x−4x+log(x)=−−x−4−x+log(−x) - No so, the function not is neither even, nor odd