Let's review the most colloquial way possible mathematical concepts that have nothing to frighten, we will try to make them as intuitive as possible for you to succeed if you have them examine you or to simply find pleasure in their understanding.
The function is a relation that links the independent variables with the dependent variables, such as an independent variable x may be the age of a child and the dependent variable is the height of the child, the role that relates will be a proportional relationship of the type y = kx where k is a number that gives old multiplying height.
This function can be represented on axes Cartesian placing the values \u200b\u200bof x the horizontal axis or abscissa and the corresponding and on the vertical axis or ordered in this way linking the pairs of points we get a straight in the example, so that function was more representative of reality should add a value b which would be the day of birth weight, so the function would be y = kx + b, is also very common and replace f (x) being f (x) = kx + b.
k value is also called the slope of the line and is a value that gives us an idea of \u200b\u200bthe inclination leaving the line joining pairs of points (x, y).
This slope is numerically equal to the value of the trigonometric tangent of the angle between the line with the x-axis, we write k = tg alpha being the angle alpha.
Also called ab intercept to be the value of y when x is zero.
This case is very simple is the case in which the function is represented by a straight line, but a function is used to express many phenomena in many sciences such as physics or economics , we some independent variables whose relationships give us the dependent variable in the simplest case of a single independent variable x can easily represent the function in Cartesian axes line up to look like her example, a parabola if exponent 2 appears in the independent variable that is y = kx2 or parabolic curves look for other exponents.
are also very representative of scientific phenomena and the exponential curve logarithmic curve.
In general cases the curve will look more or less snake-like functions and polynomial which is equal to a combination of additions and subtractions of powers of the variable x, or appearance of such hyperbola with two branches when the function is a fraction of polynomials with variable x in the denominator.
We will introduce a concept causing terror, but has to be very intuitive, the derived function of another function, usually represented by y 'or f' (x) or dy / dx.
Conceptually derived function is defined in another function that gives us the values \u200b\u200bof slope of the tangent line to the first function at each point x.
It is of great utility to study functions as we reported the appearance of the function f (x), ie when the value to take f '(x) is greater than zero the say that role is growing, this is that with increasing x increases y.
The opposite case, if the derivative function f '(x) is less than zero say that the function is decreasing, that is to increase and will decrease the x .
And it is important Cundo f '(x) is set to zero because we have a maximum or minimum value of the function f (x), ie a ridge or a valley of the curve.
A practical use for this are the problems of maximum and minimum which normally have a function z which depends on two variables x and y, ie z = f (x, y) ; but usually these variables are not independent, there is a relationship between them dependence y = g (x) where g is another function
Example: The square is the minimum figure for a given area perimeter.
demonstrated that given an area to the smaller rectangle is the square perimeter.
Let x and y sides, so that A = x * and equation of conditions that meet the dependent variables.
l E perimeter P = 2x +2 and
As y = A / x replacing the role that we want to minimize, is
P = 2x +2 (A / x)
P = (2x ^ 2 +2 A) / x ;, what role dP / dx = 0 for the x that makes the minimum perimeter
dP / dx = (4x ^ 2 - 2x ^ 2-2A) / (x ^ 2) that equal to zero
2x ^ 2-2A = 0 so that x is the square root of area A being the same value for y.
Finally we introduce the concept of Integral or primitive function which is none other than simply an inverse relationship between functions, ie if f '(x) is derived function of f (x) is said that f (x) is therefore primitive or integral function of f '(x) = F (x), the definition is therefore a logical relationship.
Then there are practical methods to compute derivatives and integrals.
Should be noted that while any function that can be derived according to the definition of a derivative function will always have a tangent line at each point and the derivative is the role to you the value of the slope of that tangent line.
Not all functions can be integrated, since to have primitive function must be derived from someone and that does not happen for any function, only those obtained by deriving another.
I hope I have shed some light on these beautiful mathematical concepts