Hot Math How-Tos
How To: Find the equation of a perpendicular & parallel line
This video shows how to find the equation of the line perpendicular and parallel to a given line. The video starts off with an example, given the lines and the slopes (m). When 2 lines are parallel to each other, they have the same slope. When 2 lines are perpendicular to each other, the slopes multiplied together will give -1. Knowing these rules, the tutorial maker provides an example with numbers. He then leads each step of the process. Each step is written out in either black, red, blue o...
How To: Find the volue and surface area of a cylinder
This video both shows the viewer how to calculate the volume and surface area of a cylinder. It also explains what these different numbers mean. The volume is the amount of ‘matter’ that the cylinder can hold. The surface area is literally the area of the cylinders curved face and the two end circles.
How To: Use a protractor to measure an angle
This video in the Education category will show you how to use a protractor to measure an angle. This video is from Brightstorm. In Geometry it is important to know how to measure an angle. This is a very simple and easy process. In order to measure an angle, you will need a protractor. Every protractor has a base and a center point marked on the base. You will put the center point on the vertex of the angle. Then align the base line of the protractor perfectly on one side of the angle. Now ch...
How To: Convert fractions to decimals
This video explains how to convert fractions to decimals by providing a good example. 1. To better explain the notion draw a box divided into sections to represent the 1 whole. 2. In this example the fraction used is 7/10. So, you have to color in 7 out of the 10 sections that make up the box. 3. To make the conversion to a decimal is now even simpler. Since not all the boxes are shaded the number must be less than 1, so start by writing 0. 4. The next step is to check the number of boxes you...
How To: Simplify square roots w/ product & quotient rules
In this math tutorial, you will learn how to simplify square roots with product and quotient rules. To begin, you will need to multiply the square roots so that the two square roots in your equation are reduced down into one. The rule for non-negative "A" and "B" is that the square root of "A" multiplied by the square root of "B" yields the square root of A x B.
How To: Use a TI-89 to calculate nCr
This video shows you how to do a mathematical representation on computing the nCr function using a TI-89 calculator. You can write the nCr notation in different forms. It can be simplified from nCr to C(n,r). The symbol can either be read "n choose r" or "n taken r at a time" which are from it's probability applications. On the example to find "26 choose 17", go to the Home screen of the TI-89 calculator and then go 2nd 5 which is Math. Go choose probability and then to nCr to type in (26,17)...
How To: Calculate the circumference of a circle
This video shows how to calculate the circumference of a given circle. The video first describes the circumference or perimeter of a circle as the distance around the outside of a circle. To find the circumference we need either the radius or the diameter of the circle. When you know the diameter of the circle, the formula to find the circumference denoted by 'C' is 'pi' times the diameter, where 'd' is the diameter and 'pi' is a constant, the approximate value being 3.14. And when you are gi...
How To: Find the equation of a perpendicular line easily
In this video the instructor shows how to find out an equation of a perpendicular line. If you need to find the equation of a line passing through the given point and is perpendicular to another line, the first thing you need to do is compute the slope of the given line. Obtain the slope of the equation by writing it in the form of y = mx + b. Now the product of slopes of two perpendicular lines is a negative one. So the slope of our required line will be the negative inverse of the slope of ...
How To: Simplify expressions involving numeric radicals
In this video tutorial, viewers learn how to simplify expressions involving numeric radicals. This can be very frustrating to work with if you have not memorized the tables of square, cubes and fourths. If you are taking the square root of a number that is not a perfect square and you wish to simplify it, the key is to write it as the product of a perfect square or another number. This video is very descriptive and clearly explains the functions of the formula. This video will benefit those v...
How To: Work with complex numbers
In this algebra video the instructor shows how to work with complex numbers. When you have a positive number under the square root, you can easily find its value by writing it in the form of product of numbers, and then solving. That is, to find the square root of a positive number, you can find another number which multiplied by itself gives the original number. This new number becomes the square root of the original number. But when you are asked to find out the square root of a negative nu...
How To: Add decimals together
Learn how to add the decimals together in simple and easy steps. 1. First practice adding two normal digits using the traditional adding method and get your answer correctly. 2. Now to add the decimals together use the same example by including decimal points to them. 3. The adding will also be the same traditional method except that you have to place a decimal point in the exact location of your answer. 4. Now take another example (E.g.: 3. 33+4. 2) and add it in the same way by placing a ze...
How To: Find the area and volume of prisms
This helpful video gives simple step by step instructions on how to find area and volume of prisms. To find the area of a prism you must first find the area of the base, it may be rectangular, triangular, or otherwise. You must then multiply the area of the base times the height. Examples of all types of scenarios are given to better explain the method of finding the area. To find the volume of a triangular prism you must first find the area of the base. The next step is multiplying the area ...
How To: Add fractions with same denominator with Virtual Nerd
This video instructs on how to find the sum of fractions that have the same denominator. In order to do this, all that needs to be done is to add the different numerators together, then put the sum of those numbers over the common denominator. The example used is 2/9 + 1/9 + 5/9. The first step is to add the numerators which gives you 2 + 1 + 5/9. Then simplify the fraction adding 2 + 1 + 5 which equals 8. That is your numerator. The denominator does not change because it is common, so the fi...
How To: Graph the slope of a line through two points
If you want to learn how to get and graph the slope of a line using two points, you should watch this. 1. Let your two points be (x1 , y1) and (x2 , y2). Draw a straight line that connects the two points. 2. Use the formula, m = change in y over change in x , for finding the slope which is represented by the variable m. 3. The simpler form of the formula would be m = (y1 - y2) / (x1 - x2). 4. If you were given two points, just substitute the values in the given formula. 5. For example, the tw...
How To: Calculate the area of a triangle with a simple method
There are only few steps to find the area of the triangle in a simple method. First you consider a triangle, and to find the area in a simple manner just add the triangle of same properties and side lengths as same as the first one and attach to it. Then we know the formula to calculate the area of the square. Then find area of the square by side*side. Then you will get the area of the square, now divide the area by two, as we add another triangle. Then the area of the triangle will be obtain...
How To: Simplify radicals before adding or subtracting
This video in the Education category will show you how to simplify radicals before adding or subtracting. By doing this you will find all like radicals which will then ensure that you have all radicals in the simplest form. Let’s say you want to subtract square root of 45 from 3 square roots of 20. Now square root of 45 can be written as square root of 9 x square root of 5. Because, 9 and 5 are factors of 45. Similarly, 3 square roots of 20 can be simplified to 3 x square root of 4 x square r...
How To: Evaluate combinations of functions from graphs
YouTube user NotesCollegeAlgebra teaches you how to evaluate combinations of functions from graphs. You start off with a graph and some functions. (f+g)(-3), (g/f)(0) and (fg)(-6). You start looking at the graph and the first line and you get (f+g)(-3)=f(-3)+g(-3)=3+1=4. (g/f)(0)=g(0)/f(0)=2/-3=-2/3. (fg)(-6)=f(-6)g(-6)=(-3). But then when you want to find out g(-6) you realize -6 is not in g's domain. So the answer to the last equation is that it doesn't exist.
How To: Solve simple algebraic equations
This is a great series of videos showing you how to solve simple algebraic equations. The first video demonstrates solving equations using addition or subtraction, the second deals with solving equations using multiplication or division, and the third shows how to solve multistep equations.
How To: Solve 2nd degree polynomials with a quadratic equation
These videos are a great tutorial to solving 2nd degree polynomials using the quadratic equation. Through simple step by step instructions, you can learn this very basic algebraic principle.
How To: Get decimal forms of rational numbers
This video series demonstrates how to convert a rational number to a decimal. A rational number is a ratio of two numbers. In other words, these fractions can be changed into decimal form. Get decimal forms of rational numbers - Part 1 of 5.
How To: Convert recurring decimals to fractions
This series of videos demonstrates how to do conversions of recurring decimal numbers to fractions. In a few simple steps, you'll be able to transfer these repeating numbers to simple fractions.
How To: Factor trinomials with 2 variables & GCF by grouping
In the video, the process of factoring trinomials is described. A trinomial that cannot be easily factored in its original form is shown. It is simplified by pulling out the greatest common factor. After that, a trinomial that is easier to factor is shown. Next, the simplified trinomial is broken up into four terms so that factoring by grouping can be done. Once again, a common factor from each pair is taken so that two binomials are created. Once the greatest common factor is added back with...
How To: Graph linear equations using y=mx+b
This video is an instructional guide about Graph Linear Equations presented in algebraic form. It is an easy to follow, step by step guide to solving such equations using the graph intercept formula. The first example equation is Y = 2x -1 over y = mx + b. The video then shows you how to breakdown the equation into manageable sums using fractions to represent the data, and then presents the formula for interpreting the answer from these sums onto the graph co-ordinates. The second and third e...
How To: Solve a system of equations through graphing
This video shows the viewer how to solve simultaneous equations using a graph or ‘graphing’ as it is referred to. This is done by first rearranging both equations so that y is the object of both equations. The equations can then be solved via substitution – the video does not cover this. Using graphing the next step is to plot both of the lines onto the graph. This can be done by substituting varying values of x to give the y co-ordinates. The solution to the linear equation should be the poi...
How To: Use a TI89 calculator to graph linear equations
This video shows the user how to use a T189 calculator to plot linear equations. The video demonstration is done using an ‘on screen’ representation of the calculator – there are also verbal instructions. The equations are plotted on the same axis by selecting the ‘y=’ function. The corresponding values of y in terms of x are then inputted into the graphical calculator. Once this has been done for every equation you can get the calculator to display the graph. This then allows you to compare ...
How To: Write a logarithm as a sum or difference of logarithms
This video shows the method to write a logarithm as a sum or difference of logarithms. The square root of the term given is taken out as half according to the rule. Then the numerator and denominator is divided into product of factors. This is broken into the difference of numerator and denominator according to the rule. Finally, the product of factors is expressed as the sum of factors. Now we see the domain of the term. As the term is a square root of the term it should be greater than zero...
How To: Graph lines using x and y intercepts
A line is defined by two connecting points on a graph, and intercepts are the points on both the x- and y-axis, where the line intersects. This video tutorial demonstrates how to graph lines using x and y intercepts in a given area. This instructional video also graphs various examples of equations and explains the associated methodology.
How To: Factor polynomials by grouping
A factoring problem that has to be solved by grouping is easy to identify, because you can always identify if there are any similar terms in a polynomial. Now, if you find any variable common in any terms pull them out as the common leaving the rest of the terms. After pulling out the common terms you can group the rest of the polynomial. Be careful while pulling out signs. Pulling out a positive number does not effect the signs of terms in the polynomial, where as pulling out a negative numb...
How To: Figure out a tip without a calculator
To figure out a tip without a calculator, first remove the pennies amount in the bill. For example, if your bill is $23.76 becomes $23.70. To figure out a 10% tip, move the decimal point one place to the left. So, 23.70 becomes 2.370 or $2.37. Bump up that number to $2.30 or $2.40 or $2.50 cents, depending on your preference. Since 20% equals two times 10%, double the figure you computed for 10%. So, $2.30 becomes $4.60, or $2.40 becomes $4.80 or $2.50 becomes $5.00. Using this method, you wo...
How To: Add and subtract radicals
Radicals are square roots which are not integers; the square roots of 2 or 3 are examples of radicals. The presenters show simple ways of how to add and subtract such radicals. They explain that by using the method of factoring, the addition or subtraction is made very easy. If the square root of 8, for instance, is in some addition sum, it can be factored into the square root of 4 times the square root 2. Since we know that the square root of 4 is 2 this can be simplified to be 2 times the s...
How To: Solve 3 equations with 3 variables
You can solve 3 equations having 3 variables. Here are the 3 equation examples: x+2y+z=10. 2x-y+3z=-5. 2x-3y-5z=27. The goal is to reduce to 2 equations having 2 variables. Multiply bottom equation by (-1). Rewrite 2nd and 3rd equation. 2x-y+3z=-5. Add -2x+3y+5z+-27. Equals 2y+8z=-32. Go back to original equations and multiply by (-2). Then you have -2x -4-2z=-20. plus 2x -y +3z. When you add these 2 equations, the answer is -5y +z = -25. You have now reduced the equations from 3 equations do...
How To: Graph a hyperbola
This video is one in a series of videos dealing with conic sections, in mathematics. This particular video deals with hyperbolas. The teacher, Robert Ahdoot, gives an example of a hyperbola, during which he emphasizes some key points. A hyperbola is identified by an equation containing x squared and y squared, with a minus sign between them. If x is larger, the hyperbola will open to the sides, and if y is larger it will open up and down. He creates hyperbolas, demonstrating where to make asy...
How To: Factor trinomials with the "swing method"
This is a very interesting educational video on how to find the factor trinomials using the swing method. Let us take an example and find the factor trinomials for 2xsquare-13x-45. Let us use the swing method. So now we will get 2xsquare -13x-45. You have to find the suitable factors of 90. It is 18 and 5. If you multiply 18 by 5 you will get 90. You will get (x-18over2)(x+5over2). The final answer is (x-9)(2x+5). Now we have found out the factor trinomials of 2xsquare-13x-45. This swing meth...
How To: Use math rotations in pre-Algebra
On yourteachermathhelp teaches you how to use math rotations in pre-algebra. In this example, the shaded object represents the original one, while the empty object is the new, rotated one. Here, the original object has suffered a quarter of a turn, or a 90 degree turn. You can see that the top of the shaded figure or object has been turned to the left. This is in the opposite direction in which the hands of a clock move. This translates to a 90 degree turn in the counter-clockwise direction. ...
How To: Simplify square roots in math
In this video the instructor shows how to simplify radicals. A radical is nothing but another name for a square root. To find the square root of a simple number the first thing that you need to do is factor it. If you need to compute the square root of a number, you first need to find a number which multiplied by itself gives the original number under the root. For example, to find the square root of 9, you need to find a number which multiplied by itself gives 9. Here the answer is 3. When 3...
How To: Solve rational equations easily
This video revolves around solving rational equations in Algebra 2. When you are given a rational equation, you have to find the greatest common factor and multiply all fractions to get that common factor. If a fraction already has that common factor, then no further step is necessary for that one. Next, you have to multiply all fractions by the greatest common factor to get rid of all denominators. Finally, the remaining equation is simple math and you only need to solve the equation for the...
How To: Find a percentage of a number
This video in the Education category will show you how to find a percentage of a number. For example, what is 12% of 56? The simple way to do this is to find 10% of 56; which is 5. 6. Then you find 1% of 56 is .56. Then you add 10% plus 1% plus 1%, that is, 5. 6 plus .56 plus .56; which is 6. 72. And that’s the answer. The other way to do this is to make decimal out of 12; which is .12. Now multiply .12 by 56 and the product is 6. 72. These are the two methods of finding out a percentage of a...
How To: Simplify expressions involving algebraic radicals
In this video tutorial, viewers learn how to simplify expressions involving algebraic ratios. In some ways, simplifying algebraic radicals is easier than numeric radicals. When we are working with square roots, we need to find the highest even power of a variable to act as out perfect square. When working with cube roots, we look for the highest multiple of 3 as an exponent for our perfect square. This video is very descriptive and clearly explains all the functions of the formula. This video...
How To: Understand parabolas
The instructor in this video uses humor to teach people math, which is not a favorite subject for many. The video goes on to teach the students in the video different ways to cut the conic sections into different shapes. The teacher then focuses on parabolas and defines the formulas. The formula is y = x^2. The rest of the video dissects the equation breaking it down into much more meaningful statements so that the average human being who is not very good at math can understand the equation. ...
How To: Add and subtract fractions with different denominators
This video is a simple math video showing how to add and subtract fractions using different denominators. It begins with a man explaining briefly and sitting in front of a piece of paper. He writes out a group of fractions each one with different denominators, ending in three and five. To add appropriately, on must find a common denominator, which is fifteen. So he multiplies each by five and three, raising the denominators to fifteen. This will raise the fractions to six-fifteenths and twent...