Posts Tagged ‘a’
Thursday, December 10th, 2009
Inverse Image of Sets
Description
A detailed tutorial on the inverse image of sets. Step by step tutorial on the inverse image of sets for reference. Knowledge of the inverse image of sets is important in advanced discrete mathematics courses.
Overview
Say that you have a function f: A –> B. Then, X is a subset of A and Y is a subset of B. The image of X or the image set of X is f(X) = {y belongs to B: y = f(x) for some x belonging to X}. The inverse image of Y is defined as f^-1(Y) = {x belongs to A: f(x) belongs to Y}. The inverse image is simply a reversed form of the image. Often when asked to find the inverse image, it will help to set up a drawing of the image of the function, connecting everything where it needs to go. Then to find the inverse you simply reverse your work.
Tags: a, b, connect, diagram, discrete math, form, function, image, image set, inverse, mapping, picture, reverse, set, subset, x, y
Posted in Discrete Math | No Comments »
Tuesday, November 24th, 2009
How to Find the Absolute Value of a Complex Number
Description
A detailed tutorial on the absolute value of a complex number. Step by step tutorial including several examples on the absolute value of a complex number for reference.
Overview
The absolute value of a complex number is a little different than the absolute value of a real number, because complex numbers deal with imaginary numbers. However, the answer is still a non-negative real number, just like the numbers you deal with in other math classes every day. Say that a complex number z is equal to a + bi, where i is an imaginary number. The |z| is equal to the square root of a^2 plus b^2. In other words, square both a and b, add them together, and find the square root in order to have to absolute value of a complex number z.
Tags: a, absolute, add, addition, b, complex, imaginary, number, real, root, square, squareroot, sum, trigonometry, z
Posted in Trigonometry | No Comments »
Friday, November 20th, 2009
Overview of the Preimage of a Set
Description
A detailed tutorial on the preimage of a set. Step by step tutorial including several examples of the preimage of a set for reference.
Overview
The preimage of a set is defined over a function. If there is a function over A and B, then we can say that y = f(x), provided that (x, y) belongs to f. Based on this definition, x is the preimage of y under f. To find the preimage, simply look for the value of x that matches with the proper value of y in any function of ordered pairs in A and B.
Tags: a, b, belongs, coordinates, defined, definition, discrete math, f, function, image, ordered pairs, preimage, set, theory, value, x, y
Posted in Discrete Math | No Comments »
Friday, November 20th, 2009
How to Pick Variables
Description
A detailed tutorial on how to pick variables. Step by step tutorial including several examples of how to pick variables for reference.
Overview
Variables are letters picked to represent unknown values in expressions and equations. Usually they are lowercase, but they can be made uppercase. When trying to pick a variable, you must choose wisely. x is the most common variable, followed by n. x is picked because people associate it with the unknown, and n is picked because it stands for “number.” The variable should be easily recognizable – you should not use a variable that looks like another number or some symbol of a mathematical operation. You should check to see what is included in your equation – for instance, m stands for slope, so if you are doing an equation with slope you need to pick a different variable to avoid confusion. And you should always pick a variable that makes sense – the first letter of your subject matter usually works quite well.
Tags: a, algebra, b, c, choose, equation, expression, lowercase, m, mathematical, n!, number, operation, slope, symbol, unknown, uppercase, value, variable, variables, x, y, z
Posted in Algebra | No Comments »
Thursday, November 5th, 2009
Saddle-Point Approximation Explained
Description
A detailed tutorial on saddle-point approximation. Step by step tutorial including several examples of saddle-point approximation for reference.
Overview
Saddle-point approximation is also referred to as the method of steepest descent and Laplace’s method. It is a way of approximating integrals in the form 
. f(x) is some twice-differentiable function, M is a large number, and the integral endpoints a and b have a possibilty of being infinite.
Tags: a, approximation, b, Calculus, descent, differentiable, function, infinite, infinity, integral, Laplace, large, m, method, number, point, saddle, saddle-point, steepest, twice, twice-differentiable
Posted in Calculus | No Comments »
Friday, October 30th, 2009
How to Determine the Point of Discontinuity
Description
A detailed tutorial on determining the point of discontinuity. Step by step tutorial including several examples of how to determine the point of discontinuity for reference.
Overview
A point of discontinuity is where the graph of a function is discontinuous – this means the graph has a breaking point in it, it break off for a while and starts again somewhere else, or there is a small open circle somewhere on the graph, which would be an actual point of discontinuity. In mathematical terms, the point of discontinuity is the point at which the graph of the function is undefined. Simply look a value of x that will make the function undefined, and that is your point of discontinuity. This is easiest to determine when your function is a fraction.
Tags: a, algebra, break, discontinuity, discontinuous, fraction, function, graph, point, start, stop, undefined, x
Posted in Algebra | No Comments »
Tuesday, October 27th, 2009
The Cross Product of Vectors
Description
A detailed tutorial on the cross product of two vectors. Step by step tutorial including several examples of how to find the cross product for reference.
Overview
A cross product is very similar to a dot product. However, the result of a cross product is a vector, and the result of a dot product is a scalar. In mathematical terms, the cross product can be defined as 
. Theta represents the meausre of the angle between a and b, and n is a unit vector perpendicular to both a and b. The vector this forms is a right-handed system.
Tags: a, algebra, b, cross, dot, n!, outer, perpendicular, product, right-handed, rule, scalar, system, unit, vector
Posted in Algebra | No Comments »
Tuesday, October 27th, 2009
Introduction to Vector Equality
Description
A detailed tutorial on how to determine if two vectors are equal. Step by step tutorial including several examples of vector equality for reference.
Overview
Vectors are said to be equal if they have the same magnitude and direction. They must also have the same coordinates. Using this logic, it is possible to determine if you have two vectors 
and 
, they are equal if 
.
Tags: a, algebra, b, coordinates, direction, E, equal, equality, length, magnitude, vector
Posted in Algebra | No Comments »
Friday, October 16th, 2009
Overview of the Conjugate Zeros Theorem
Description
A detailed tutorial on the conjugate zeros theorem. Step by step tutorial including several examples of the conjugate zeros theorem for reference.
Overview
The conjugate zeros theorem states that if a + b * i is a zero of a polynomial with real coefficients, then so is a – b * i. The conjugate zeros theorem can be proved by taking any function in this form and setting it equal to zero. The conjugate zeros theorem makes many equations easier to solve, especially complex equations when you get to higher levels of math.
Tags: a, b, Calculus, complex, conjugate, equations, function, i, imaginary, Math, number, theorem, zero, zeros
Posted in Calculus | No Comments »
Friday, October 9th, 2009
Ordered Pairs Explained
Description
A detailed tutorial on ordered pairs. Step by step tutorial including several examples of how to solve problems using ordered pairs for reference.
Overview
An ordered pair is a set of two elements that is in a specific order, that is, (a, b) would be different from (b, a), unless a = b. In ordered pairs, the order of the elements are extremely important. And example of a well-known ordered pair would be a Cartesian coordinate.
Tags: a, arithmetic, b, cartesian, coordinate, element, equals, graph, Math, order, ordered pair, pair, set
Posted in Arithmetic | No Comments »
