Words that Describe Patterns

Key Questions

  • How do you write an expression when given a table of values?

    Answer:

    It depends...

    Explanation:

    I note that example problems of the kind "here's a table - what is the function?" can take various forms:

    (1) The table contains two pairs of values and the expected answer is a linear function in the form y = mx + c or similar.

    (2) The table contains more than two pairs of values, but still exactly linear, looking for a function of the form y = mx + c.

    (3) The table contains several pairs of exact values, with an expected answer being a simple polynomial function, an exponential function or some other simple function (e.g. sinusoid).

    (4) The table contains approximate values (e.g. measurements from an experiment), from which one is expected to find a line or a simple function of best fit. The type of function may or may not be specified.

    The different types of problem require different techniques, but here's a general solution for cases (1), (2) and polynomial examples of case (3)...

    Given a table with distinct x values x_1, x_2,..., x_n and corresponding y values y_1, y_2,... y_n consider the polynomial:

    ((x-x_2)(x-x_3)...(x-x_n))/((x_1-x_2)(x_1-x_3)...(x_1-x_n))

    Note that when x=x_1 this will take the value 1, since the numerator and denominator will be the same, whereas when x = x_2,...,x_n it will take the value 0.

    With this in mind, consider the polynomial:

    f(x) = ((x-x_2)(x-x_3)...(x-x_n))/((x_1-x_2)(x_1-x_3)...(x_1-x_n))y_1 + ((x-x_1)(x-x_3)...(x-x_n))/((x_2-x_1)(x_2-x_3)...(x_2-x_n))y_2 + ... + ((x-x_1)(x-x_2)...(x-x_(n-1)))/((x_n-x_1)(x_n-x_2)...(x_n-x_(n-1)))y_n

    This is a polynomial of degree at most n-1 which takes the value y_1 when x = x_1, y_2 when x = x_2, all the way up to y_n when x = x_n. That is, it is a polynomial function which fits that data.

    From this point you might want to multiply out the expressions to get the polynomial into standard form.

    In practice, there are often simpler ways to get to a nice linear or polynomial function.

    George C. · 2 · Jul 25 2018
  • What are Words that Describe Patterns?

    Answer:

    Read below...

    Explanation:

    Patterns are ways or appearance of something (Object, Value, Anything) is being defined or arranged.

    Words that describe pattern are as follows;

    Sequence (Increasing or Decreasing)

    Progression (Arithmetical, Linear or Geometric)

    Quadratic ( ax^2 + bx + c)

    Binomial (1 + x)^n

    Polynomial (ax^3 + bx^2 + cx + d)

    Shape patterns like Polygons (Triangle, Quadrilateral, Pentagon)

    etc..

    Note: All values, object must follow the defined way of arrangement, that is why it is called a pattern, it doesn't change!

    Jumbotron · 1 · Oct 4 2017

Questions

Expressions, Equations, and Functions