Math How-Tos
How To: Add & subtract rational expressions
In this video the instructor shows how to add and subtract rational expressions. When you have an addition or subtraction problem of rational expressions, first look and compare the denominator of all the terms. If all of them have the same denominator then the expression can be written as a fraction whose denominator is the original common denominator and whose numerator is the sum of numerators of all the other terms. Simplifying the numerator by adding and subtracting the like terms gives ...
How To: Complete the square and solve the quadratic equation
In order to solve a quadratic equation by completing the square, take a quadratic equation and make sure that the coefficient of the first squared term in one. If it is not factor it by pulling the term out to get it to one. Now just write down the first two terms in side a bracket and after it add the third term. Now take the coefficient of the x term and take one half of it and square it and put that number back into the bracket. Now as you added a new number, to cancel it out subtract it f...
How To: Solve direct & inverse variation word problems
In this video the instructor teaches about direct and inverse variation. Two variables x and y are said to be in direct variation with each other if you can write them in the form y = K * x. The value of y varies directly corresponding to the value of x. Y is said to be directly proportional to x. If you have a sample value of x and y, you can substitute the values in the above equation to compute the value of the constant K. Using this formula you can always find the value of one variable x ...
How To: Figure out the slope of a line
In this video you will learn how to find a slope of a line. The man in the video shows in a practical and easy way, how to do it with formulas. First he teaches how to find slopes of lines containing both negative and positive points. He shows with formulas how to do it. He teaches how to find slopes on a flat line and demonstrates that the slope of it is equal to 0. Next, he teaches a "trick" to help students learn how to identify zero and no slope lines. In the last example, he demonstrates...
How To: Simplify a complex fraction w/ binomial denominators
To simplify a complex fraction, turn it into one fraction on the top divided into a fraction on the bottom. Once this is complete, you will turn the division into the two into a multiple by the reciprocal, factor, and then cancel. To make a division, find the lowest common denominator of both the top and the bottom. Once you get this division equation, look carefully at the equations. If something can be easily canceled, go ahead and cancel it out at this time. If you cannot cancel anything a...
How To: Find the parallel line to a given equation
This videos explains how one can easily find the parallel line to a given mathematical equation. He starts by explaining what it means for two lines to be parallel mathematically speaking. Defining two lines, then comparing the slope of both lines you can mathematically determine that they are in fact parallel. He then moves to common math problems found on tests where you are given a point and a linear equation. He then forms a T-table with one column being line one and line two and illustra...
How To: Find the geometric mean
It doesn’t matter how long ago your last geometry class was, you can still impress your friends by finding a geometric mean. The geometric mean can be used to find the average of numbers with out unusually high or low results effecting the result.
How To: Draw a hypercube
This clip shows how you can draw a hypercube, which is a complex shape composed of cubes. You start with a series of equally spaced horizontal lines. Then you draw a vertical line from the origin (o, o, o). From the same point, you draw a horizontal line of the same length and two more lines at 45 degrees and 135 degrees from the horizontal. The vertical line and the 45 degree line form two of the vertices of one of the cubes. The vertical line and the 135 degree line form two of the vertices...
How To: Determine the area of a trapezoid
Need to figure out the area of a trapezoid for a household project? Even if you just want to sound smart, there is a simple formula that can be used every time you need to find the area of a trapezoid. Try the formula and see how good you are at geometry.
How To: Solve equations & inequalities with absolute value
In this tutorial the instructor talks about various strategies for solving equations and inequalities involving absolute value. To do this the first step is to isolate an absolute value. An absolute value is exactly equal to a number. If that number is less than zero then there is no solution. So, if you have an absolute value that is less than a number it means that the real value lies in between negative and positive value of that number. If your number is less than zero then it is empty se...
How To: Graph using the slope intercept equation of a line
This video shows us how to draw a linear equation using the slope and intercept technique. First, the narrator explains how to simplify the equation in order to get the slope and intercept out. He then shows how the coefficient of x equals the slope and the constant term tells us the y position of the intercept point. The technique for drawing the final line is plotting the intercept at the right height on the y axis, then running for some distance along the x axis and rising some amount. Thi...
How To: Add rational expressions with different denominators
This video shows the method to add rational expressions with different denominators. The first step in this process involves finding the LCD. After this is done, the numerator and denominator are multiplied by a specific number so that the fractions are rewritten with common denominators. In the second step the numerators are added or subtracted according to the problem with LCD in the denominator. Simplify the numerator by adding or subtracting like terms. After this, we get a rational expre...
How To: Find the percent increase or decrease in a quantity
This video shows us the method to find the percent increase or decrease in a quantity. This can be done in 30 seconds. The formula states that the percentage increase or decrease is equal to the product of the ratio of amount (increase or decrease) and the original amount and 100. This is explained by two examples. In the first example the amount of increase of the price of groceries is found by taking the difference of the new price and the old price. This is divided by the original price an...
How To: Understand the basics of matrices
In this video you learn how to understand the basics of matrices. The video includes how to do matrices with addition, subtraction and multiplication. The teacher explains in this exercise that you will need to know the number of rows and columns. He breaks down all of the steps required to solve these problems. Not only does he show how to understand the basics of matrices, but he does it dressed up like a king and with a little reggae music. You can hear the class's reactions to his jokes i...
How To: Find the equation of a circle given: center & tangent
In this video, the instructor shows how to find the equation of a circle given its center point and a tangent line to it. To do this, take a graph and plot the given point and the tangent on that graph. Now, from the center of the circle, measure the perpendicular distance to the tangent line. This gives us the radius of the circle. Using the center point and the radius, you can find the equation of the circle using the general circle formula (x-h)*(x-h) + (y-k)*(y-k) = r*r, where (h,k) is th...
How To: Solve systems by substitution
You can solve systems by using the substitution method. Here are two examples. One says y=3x+2 and the second says 7x-4y=7. The math teacher explains that if y is the same thing as 3x+2, then 3x+2 can be substituted for y in 7x-4y=7. Once it is substituted, your equation will then read 7x-4(3x+2)=7. The next step is to solve for x. Once you have worked out this equation, you will see that x=-3. Finally, your last step is to solve for y. To solve for y, simply substitute x with -3. The equatio...
How To: Translate a word problem into algebra
This video shows the method to change a word problem into algebra and to identify rational numbers among a group of numbers. In the first part of the video we take a word problem namely - The product of 9 and seven, less than a number. 9 multiplied by something can be expressed as 9(). The unknown number can be expressed as 'x'. Seven less than a number can be expressed as x - 7, so that the final equation becomes 9(x - 7). In the second part we are given a list of numbers. A rational number ...
How To: Shift a graph
This video will demonstrate exactly how to shift a graph on a x,y axis. When shifting a graph on the x axis you will need to replace x with x-h; where h is the variable to shift the graph. No matter how far you need to shift a graph, h is always the number of units you are shifting; shifting up or right is represented as a positive and down or left is negative. Just plug in your units into your equation and you will have your shifted graph.
How To: Translate a sentence into math symbols
We will be translating the sentence "twice y differs from 5 by more than two, “into a mathematical equation. The word twice generally means two times, so 2*y (because y comes next in the sentence). Differs normally means is different and a difference from something in a mathematical sentence means subtraction most of the time, thus minus five. We don't know if we’re talking about below 5 or above 5 on the number line, so we put absolute value around the equation. More than implies a greater t...
How To: Find points on y-axis a certain distance from a point
This is video on mathematics. It specifically deals with geometry. The video describes how to determine where the y-intersects are when a point and distance to the y-intersect are given. The author starts out by giving an example ordered pair. The speaker next shows an example of how to solve such a problem. The speaker uses the distance formula along with the given distance and x-coordinate in order to solve for the y-intersect values in question. Most of the video entails solving this example.
How To: Simplify square roots
This is a video tutorial on how to simplify square roots. To simplify square roots, one must have the knowledge of splitting numbers into prime factors. For example,12 can be split into 4*3 and further more into 2*2*3. Here we see that all the factors are prime numbers. So the square root of 12 can be written as 2*square root of 3(as shown in the video). The method used in the video is applicable for simplifying any square roots as any number can be split into prime factors. Follow the video ...
How To: Solve a linear system by elimination method
This video is about using the elimination method to solve a linear system. The lady presenting this video says that elimination method means that one of the two variables has to be eliminated while adding up the two linear equations. She then explains the example equations 6x-2y=66 and 5y=-29-2x. She asks you to first line up x and y. So the second equation is rewritten as 2x+5y=-29. Then she says that, to eliminate a variable, we should have their variables equal in value but of opposite sig...
How To: Handle missing terms in algebraic long division
In this tutorial you are shown exactly how to do algebraic long division when terms are missing in the polynomial. Follow these steps and you can divide whatever you'd like:
How To: Divide rational expressions
In this video the instructor shows how to divide rational expressions. To divide rational expressions follow this simple four step approach. In the fist step change the division to multiplication by flipping the second fraction. Now the original division simplifies to multiplication. In the second step factor the terms of numerators and denominators in the two fractions. In the third step cancel the common terms in the numerator and the denominator. Now finally in the fourth step multiply all...
How To: Complete a proof involving angles
Money math is back for a chill lesson on completing a proof involving angles. This proof touches on complementary angles, definition of congruent angles, Angle Addition Postulate, and substitution. YAY MATH! This video will demonstrate exactly how to complete a proof involving angles.
How To: Calculate a limit by getting a common denominator
This video explores how to get the limit by getting a common denominator. When you try and plug in a limit, for example when the denominator goes to zero, you can get yourself into a situation where you get the answer (0/0) which is mathematically irrelevant. To solve this problem, you must find a common denominator and split the problem up into its various parts. By setting common denominators in the numerator, you can then flip the fraction around allowing you to properly calculate the limi...
How To: Multiply mixed numbers for recipies
Despite what we all argued in school, math does come up in daily life. When those dreaded fractions are staring you in the face remember these steps and you will be multiplying in no time. Practice always helps.
How To: Add rational expressions
This is the video about how to add a rational expression. So to add a rational expression first of all find the common denominator. To find the common denominator, just find the least common multiple (LCM) of the denominators. There are at least a couple ways of doing this. To convert each fraction to the common denominator, you multiply each denominator by what it needs in order to turn it into 6x. For instance, in the x+4/5x, the denominator needs to be multiplied by 6x, since 6xX5x = 30x. ...
How To: Graph piecewise defined functions
In this video the instructor shows how to graph a piecewise defined function. A piecewise defined function is a function that is defined in separate pieces. In these kind of functions, for different ranges of the value of x, you are given different small functions, all of which together make the whole function. This means your equation of the function is given in the form of smaller functions. Now to graph these kind of equations all you have to do is graph the individual equations in the sam...
How To: Find the volume of a pyramid
A pyramid is a three dimensional version of the triangle. In this video, learn how to find the volume of a pyramid. Finding volume is the next step after you learn how to find 2D area. Check out this tutorial and soon you will be tackling 3D objects just as easily as you learned their 2D cousins.
How To: Calculate percent error in chemistry lab activities
If you want to know how to calculate percent error easily, you should watch this video. Error is the amount of deviation from accurate values. Error calculation is not possible, unless you make a quantitative measurement of the various quantities involved in your experiment. Measurement can help us in calculating errors and knowing how right we are in our theoretical models. In calculating percent error, We need to get the experimental value and the value which you are aiming at, which is the...
How To: Convert temperature measured in Celsius to Fahrenheit
This video teaches how to convert a value in Celsius to Fahrenheit in simple steps. First take a paper and marker and keep in mind a Celsius value (e.g-32) to convert into Fahrenheit. Now use the formula to convert Celsius to Fahrenheit which is F=1.8(32)+32. Use a calculator to calculate the formula and you will get the result as 89.6 Fahrenheit. Now round it off the and your final result will be 90 degree Fahrenheit.
How To: Multiply mixed numbers with whole numbers
This video shows us how to multiply mixed numbers with the whole numbers. First thing you need to do is to change the mixed number into an improper fraction by multiplying the denominator with the whole number and add the resulting number with the numerator. The resulting number will be placed as a numerator with the denominator being the same. Next, is that we can't multiply a fraction with a whole number. So we need to change the whole number into a fraction and this is done by putting the ...
How To: Divide integers
This short video shows basic math integer division. It shows examples of how dividing a positive integer with another positive integer will yield a positive result, whereas diving a negative integer with a positive integer will yield a negative result. This exemplifies the fact that when the signs are different in division, the result will always be negative. This video can definitely help young math students get a better grip of basic integer division and thus have a stronger footing from wh...
How To: Solve linear equations w/ the multiplication property
This video demonstrates how to solve a linear function with rational coefficients by multiplying by the reciprocal of the coefficient. The reciprocal is just a fancy way of saying the numerator and denominator are swapped. Two sample problems are solved using this method. Multiplying each side of the equation by the reciprocal of the rational coefficient of the variable 'x' is an allowed operation, but only because both sides are multiplies by the the same amount. The teacher then demonstrate...
How To: Find the slope from a graph
To do this, there are many ways to approach this problem. One way is to look at the change in Y over the change in X by looking at the points on the graph. Another way is to use the equation Y2-Y1 over the equation X2-X1. In other equations where you are given a graph, you may be asked if the slope is positive, negative, or zero. To determine this, look at the line in the context of moving from left to right along the graph. If the line graphed is going down as you move from left to right, th...
How To: Add or subtract fractions with math
Learn how to add or subtract fractions with math in simple steps. First convert any story line you have into a fraction. Now you have to convert the denominators so that both the fractions have the same. To do so multiply both the numerators and denominators with the same number. Now when you have the same denominators add the numerators to get the answer. Reduce the fractions to a lower value if you wish. Try this out with some other examples.
How To: Multiply rational expressions
The video describes the basic process of multiplying two rational expressions. The problem illustrated in this video involved multiplying rational expressions of monomial terms with integer coefficients. As with the other example problems, we follow the steps of: factoring, canceling, and multiplying. Because these terms are monomials, no factoring is required (but we still state it as a step for similarity to solving other problems). We then find the greatest common divisor for both terms to...
How To: Find the circumference of a circle
Use a simple mathematical formula to find the circumference of a circle. The circumference of a circle can be determined by using the formula 2 times pi times the circle's radius. Pi is equal to 3.14. If a circle's radius is 10 centimeters, first multiply pi times 2. Pi, or 3.14, times 2 is 6.28. The next step then is to multiply 6.28 times the circle's radius. Since the circle's radius is 10 centimeters, multiply it by 6.28. This gives you 60.28. 60.28 inches, then, is the circumference of t...
How To: Complete the square to graph a quadratic function
In this tutorial the instructor shows how to complete the square to graph a quadratic function using transformations. You can do this by transforming your equation in a series of steps. First make the coefficient of the square term to one by pulling out its numerical coefficient. Now to complete the square of the first part add half the coefficient of the variable with a degree one. Now to maintain the original value of the equation also make sure that you subtract the same value from the equ...