Study of a function
By a.zampa

Period: 100 to 199
Determining the domain
The (natural) domain of a function is the set of all real numbers to which the function assigns a value 
150
Solve inequalities
You need to impose the (existence) conditions under which each operation (such as division, square root, ...) or function (such as logarithms, ...), present in the analytic expression of the given function, can have a value (e.g. you can't divide by 0, you can't take the square root of a negative number, ...) 
Period: 200 to 299
Determining symmetries
Determine if the graph of the function is invariant under some type of geometric transformation 
233
Parity (axial / central symmetry)
The function is even if its graph is symmetric with respect to the ordinate axis, i.e. the value of the function is invariant under change of sign of the independent variable The function is odd if its graph is symmetric with respect to the origin of coordinate axis, i.e. the value of the function changes sign under change of sign of the independent variable 
267
Periodicity (translation)
The function is periodic, with period T, if its graph is invariant under horizontal translation by an amount equal to T, i.e. its value does not change when adding T to the independent variable 
Period: 300 to 399
Determining sign and intersections of the graph with coordinate axes
Determine the regions of the cartesian plane wher the graph of the fuction is placed 
325
Intersection with the axis of ordinates
If 0 is an element of the domain then the graph intersect the axis of ordinates at the point whose ordinate is the value associated to 0 by the function 
350
Intersections with the axis of abscissas
The intersections of the graph with the axis of abscissas correspond to the zeroes of the function: to find them you need to solve an equation 
375
Sign of the function
The sign of the function allows to know if the corresponding point of the graph is above or below the axis of abscissas. You can obtain the set of positivity and the set of negativity of the function (together with the set of zeroes) by solving a single inequality 
Period: 400 to 499
Classifying discontinuities/singularities
Analyse the behaviour of the function near the accumulation points of its domain where it is not continuous or undefined by means of limits 
425
Jump discontinuty / singularity (of the first kind)
The left and right limits are different real numbers 
450
Essential discontiunity / singularity (of the second kind)
At least one among the left and right limits is infinite or does not exist 
475
Removable discontinuity / singularity (of the third kind)
The left and the right limit are the same real number 
Period: 500 to 599
Determining asymptotes
Analyse the behaviour of the graph at infinity to check if it approximates some stright line 
525
Vertical asymptote
The graph of a function has a vertical asymptote if and only if the limit of the function when the independent variable tends to a real number is infinite 
550
Classifying inflection pointsHorizontal asymptote
The graph of the function has anhorizontal asymptote if the limit of the function when the independent variable tends to infinity is a real number 
575
Slant asymptote
For a slant asymptote to the graph of a function to exists three conditions need to be met 
Period: 600 to 699
Determining growth (monotonicity)
Find the regions of the domain where the function is increasing or decreasing 
625
Calculate the (first) derivative
The (first) derivative of the function hosts information about the slope of the line tangent to the graph, hence the study of the monotonicity of the function is performed by solving a suitable inequality 
650
Increasing function
The function is increasing in every interval of its domain where the sign of its (first) derivative is positive 
675
Decreasing function
The function is decreasing in every interval of its domain where the sign of its (first) derivative is negative 
Period: 700 to 799
Classifying stationary (critical) points
Determine the position of estremals and of inflection points with horizontal tangent 
720
Critical points
Zeroes of the (first) derivative are called critical (or stationary) points: they correspond to points of the graph where the tangent line is horizontal and generally, but not always, they signal a change of monotonicity (in which case they are also called extrema) 
740
Local maximum
A local maximum, which is one f the two inds of extremum, is a critical point for which there exist a left neighbourhood where the (first) derivative of the function is positive, and a right neighbourhood where the derivative is negative 
760
Local minimum
A local minimum, which is one f the two kinds of extremum, is a critical point for which there exist a left neighbourhood where the (first) derivative of the function is negative, and a right neighbourhood where the derivative is positive 
780
Horizontal point of inflection
A horizontal point of inflection is a critical point which has a punctured neighbourhood where the (first) derivative has constant sign, i.e. it is either positive in that neighbourhood, or it is negative in that neighbourhood 
Period: 800 to 899
Classifying points of nonderivability
Understand the "branches" of th graph near points where the function is continuous but it is not derivable 
825
Corner point
A corner point is a (not isolated) point of continuity of the function where the left and right limits of the (first) derivative are distinct real numbers 
850
Cusp
A cusp is a (not isolated) point of continuity of the function where the left and right limits of the (first) derivative are infinite with different signs 
875
Vertical point of inflection
A vertical point of inflection is a (not isolated) point of continuity of the function where the left and right limits of the (first) derivative are infinite with the same sign 
Period: 900 to 999
Determining the concavity
Find in which way the graph curves with respect to the tangent line 
925
Calculate the second derivative
The second derivative of the function hosts information about the concavity of the graph, i.e. about which side of the tangent line the graph stays in a neighbourhood of the point. The function is concave up, or convex, at a point in a punctured neighbourhood of which the graph is above of the tangent line, whereas if the graph is below of the tangent line there the function is concave down, or concave. The study of the concavity of the function is performed by solving a suitable inequality 
950
Concave up (convex) function
The function is concave up (convex) in every interval of its domain where the sign of its second derivative is positive 
975
Concave down (concave) function
The function is concave down (concave) in every interval of its domain where the sign of its second derivative is negative 
Period: 1000 to 1099
Classifying inflection points
Determine the type of the points whhere the graph changes its concavity type 
1025
Points of inflection
Zeroes of the second derivative signal a possible change of behaviour of the function with respect to concavity. If the sign of the second derivative changes crossing a zeroe then the corresponding point of the graph is called apoint of inflection (the graph "flexes" at that point) 
1050
Ascending point of inflection
An ascending point of inflection is a point for which there exist a left neighbourhood where the second derivative of the function is negative, and a right neighbourhood where the second derivative is positive. Therefore, locally the function is concave to the left of a descending point of inflection, while it is convex to its right 
1075
Descending point of inflection
A descending point of inflection is a point for which there exist a left neighbourhood where the second derivative of the function is positive, and a right neighbourhood where the second derivative is negative. Therefore, locally the function is convex to the left of a descending point of inflection, while it is concave to its right 
1100
Drawing the probable graph
All the information collected during the study of the function allows to sketch a probable graph representing geometrically the main properties of the function