# Hot Math Posts

### How To: Determine if a point lies on a line in slope intercept

In this video the author shows how to find out if a Point lies on a Line in Slope Intercept Form. He shows it by an example where he takes a point, which is an ordered pair in the form (x, y) and a line, which is an first degree equation. Now he substitutes the values of x and y in the equation and checks if both the sides of the equation match. If it matches we can conclude that the point lies on the line. By following the method given in this tutorial you can find out if a given point lies ...

### How To: Calculate math without a calculator

Before the calculator and even the abacus was invented, there was a little instrument called the human brain that we used to do math. Remember that? While most of us turn to our trusty Ti-84s to do calculus homework or whip out our cell phone calculators to determine how much we should tip at Johnny Rocket's, it can often be much faster to use our own brains, along with a piece of paper and pencil.

### How To: Prove a triangle inscribed in a circle is right angled

When a triangle is inserted in a circle in such a way that one of the side of the triangle is diameter of the circle then the triangle is right triangle. To prove this first draw the figure of a circle. Now draw a diameter to it. It can be any line passing through the center of the circle and touching the sides of it. Now making this as the side of a triangle draw two lines from the ends of the diameter to a point on the circle. Now join the center of the circle to the other vertex of the cir...

### How To: Express a ratio as a fraction in simplest form

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to rewrite a ratio as a fraction in its simplest form.

### How To: Convert numbers in and out of standard form

In this video, we learn how to convert numbers in and out of standard form. Standard form is a useful way of writing down very large numbers and very small numbers. To do this, you will look at the number you have and ignore the zeros that are just at the end. Then, write down the basic numbers. Put a decimal point in this number to make it between one and ten. Now, write down x 10 and put the power for how many places the decimal point moved to get to the new number. This will help you write...

### How To: Find the volume of a swimming pool

In this video, we learn how to find the volume of a swimming pool. To do this, you will first need to find the measurements of all the sides that are on the pool. After this, you will plug in the measurements that you found into the equation to find the volume. This equation is: V=AH, volume= area(height). So, plug in the area and the height to the equation for A and H and then multiply these two together. Once you do this, you will find the answer! Don't forget to label the units on the fina...

### How To: Simplify surds (improper square roots)

Could you use a little help figuring out how to simplify numbers left in square root form? Watch this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this free math tutorial, you'll learn how to simplify surds.

### How To: Deal with brackets in polynomials

This how-to video shows viewers how to solve math problems with brackets in polynomials. The person in the video teaches people how to solve the problem with a positive sign before the brackets. This segment does not show how to solve the trickier problem where there is a negative sign in front of the brackets. The tutor shows everything from removing the bracket due to the positive sign, to combining the similar terms for the result of the problem. This video can help anybody deal with brack...

### How To: Calculate probability in "at least one" problems

Calculating probablities can be used to help us make decision. PatrickJMT explains how to calculate probability in an "either A or not A" scenario. The probability of A plus the probability of not A is equal to one. Therefore, the probability of A is equal to one minus the probability of not A ; P(A)= 1 - P(not A). The probability of a major earthquake in San Francisco over a period of time is used as an example. The probablity of an earthquake of a magnitude of 7.5 or greater in San Francisc...

### How To: Solve an equation with fractional powers

Solving equations involving fractional powers of a variable are not that hard to solve as they sound. In fact, just watch this video to learn a few tips and solving these type of equations will become a little bit easier.

### How To: Solve basic linear function word problems in algebra

Need some help solving linear function word problems? See how it's done with this free video math lesson. Need help finding the From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series o...

### How To: Find the area of an oblique triangle using formulas

In this tutorial the instructor shows how to find the area of an oblique triangle using different formulas. To find the area of an oblique triangle there are different formulae. The first formula to calculate the area of a triangle is area A = (1/2) * a * b * Sin(C), where a and b are the lengths of the two sides of the triangle and C is the value of the angle of the triangle that lies in between the two sides a, b. Now substitute these values in the given formula to find the area if you have...

### Find the discriminant (DELTA): quadratic equation

The discriminate of any equation in any degree plays an important role in determining the roots of that equation.

### How To: Reduce fractions to their lowest terms

This video tutorial belongs to the Education category which is going to show you how to reduce fractions to their lowest terms. For doing any operation with fractions like addition, subtraction, multiplication or division, they need to be reduced to their lowest terms. To do this look at the numerator and the denominator and decide what number can divide both of them. Continue dividing till you can no more divide them. Now you get the lowest term of the fraction. For example, 2/4 can be divid...

### 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: Plot a real number on a number line

This video tells you how to plot a real number on a number line. For example consider -3.1. You know -3.1 lies between -3 and -4. You also know -3.1 lies very close or next to 3. So all you have to do is, put a point just before -3. Now you have marked -3.1 on a number line. Similarly you can point any real number on a number line. It is quite an easy job to plot real numbers on a number line.

### How To: Find a percentage of a whole number in basic math

Need help figuring out how to find a given percentage of a whole number (e.g., 16% of 736)? Watch this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this free math tutorial, you'll learn how to find percentage values in basic arit...

### How To: Rationalize square roots

In this tutorial, we learn how to rationalize square roots. You cannot have square roots in the denominator of an equation. You need to multiply so the square root goes away. You can do this by multiplying the top and bottom of the equation by the bottom denominator. From here, this will make the square root go away, so your equation will be normal numbers. After you have done this, you will have the equation answered and you will be able to simplify it to find the end answer. You can do this...

### How To: Simplify Square and Cube Roots

Whenever you simplify a square root or a cube root you are writing them in the simplest form. This video teaches a factoring method.

### How To: Find a data point (Xi) with the Z-Score formula

In this free video math tutorial, we learn how to use the Z-Score formula to find a data point (Xi) in statistics. With mathematics, as with anything else, not everyone progresses at the same rate. Stats is no exception. Happily, in the age of Internet video tutorials, this isn't a problem. Those who progress quickly can go beyond what's being taught them and those who are struggling likewise have all the time in the world to catch up. Whether you need help finishing your homework or studying...

### How To: Find the length of a segment using the midpoint II

First of all in the given question you have to write down the values of the total length of the line segment, PS=15. The length of the line segment, QR =3. Now you have to find the value of line segment RS. Because you know that the Q is the midpoint of the line segments PQ and QS must be equal. Therefore you can find out the length of the half of the segment using the midpoint. Subtract the value of QR from QS. Given that segment PS=15 and Q is the midpoint, you can conclude segment PQ=7.5 a...

### How To: Solve simple math problems involving exponents

See how to apply exponent rules to simplify and solve equations with this free video math lesson from Internet pedagogical superstar Simon Khan. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Solve patterns and equations

This video walks you through the steps of solving patterns and equations. This excellent video shows you a clean blackboard, with the instructors voice showing exactly what to do. Don't fret, any question you may have, will be answered. Watching this video will make you feel like your back in the classroom but rather comfortably from your home.

### How To: Graph negative numbers on number line

The video begins with a piece of paper with questions 6 and 7 on from section 1.3. The narrator introduces these two questions as both having to do with graphing on a number line. Starting with question 6, which asks the person to graph -11/4 on a number line, the narrator draws a number line with the numbers up to -5 on the left, up to +5 on the right of 0 in the middle. She starts by showing -3 as an example, and then draws a black dot on the line at the point of the number 3. She then illu...

### 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: Write a sum/difference of logarithms as a logarithm

To write the sum or difference of logarithms as a single logarithm, you will need to learn a few rules. The rules are ln AB = ln A + ln B. This is the addition rule. The multiplication rule of logarithm states that ln A/b = ln A - ln B. The third rule of logarithms that deals with exponents states that ln (M power r) = r * ln M. Using these three rules you can simplify any expression that involves logarithms to arrive at a single logarithm. The instructor shows how to apply these rules to a f...

### 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: Find the common ratio of a geometric series

Interested in knowing how to find the ratio of a geometric series? See how it's done with this free geometer's guide. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Divide numbers using long division

This video focuses on how to do long division. She starts by dividing 1548 by 26, going incrementally between each value. She first take 26 into the first three numbers of 1548 (154) and gets 5, then takes the remainder of 24 (154-130) and brings down the 8 to get 248. She then divides 248 by 26 to get 9 with a remainder of 14. She then goes into some detail as to how to extract the decimal from the remainder by continuing the long division and adding zeros to the end of the divisor. At the e...

### How To: Calculate the width of a fence given its length and perimeter

From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps. With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn how to find the width of a fence when given numbers for its length and perimeter.

### 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: Calculate percentage with a calculator

This easy to understand video gives us two ways to calculate a percentage using a calculator. The video first shows us how to use the percent key on the calculator using the example of figuring out how much to tip at a restaurant. We can also convert a percentage to decimals before entering the information in the calculator and then just use simple multiplication. The instructions are easy to follow, as the video is less than a minute of watching someone use a calculator.

### How To: Multiply proper & improper fractions

So, you need a little extra help in the fractions department? No problem. In this two-part vieo tutorial, learn how to multiply proper fractions and mixed numbers in part one. In part two, learn how to multiply mixed numbers & multiply sets of improper fractions.

### How To: Solve ratio problems in basic mathematics

Need help figuring out how to work with ratios? Look no further than this free video lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test). With this installment from Internet pedagogical superstar Salman Khan's series of free math tutorials, you'll learn...

### How To: Find the domain of a function in precalculus

Looking for a primer on how to find the domain of a function in precalculus? Learn how with this free video precalc lesson. From Ramanujan to calculus co-creator Gottfried Leibniz, many of the world's best and brightest mathematical minds have belonged to autodidacts. And, thanks to the Internet, it's easier than ever to follow in their footsteps (or just finish your homework or study for that next big test).

### How To: Factor a trinomial with a negative in front

This video shows the method to factor a trinomial with a negative sign in the front. The first step is to make the first term positive. This is done by taking the negative sign out. Then we see the middle term of the trinomial. The coefficient of the middle term is a positive one in the example shown. We have to group the coefficient of the first and third term in a way so that the difference is positive one. The appropriate combination is chosen so that this becomes true. In this way the tri...

### How To: Graph x squared & the square root of x

In this video the instructor shows how to sketch the graph of x squared and square root of x. The first equation is the x squared which is y = x * x. Now to sketch this take a sample values of x and substitute in the equation to get the value of y. Similarly find the set of points for the equation. Finally plot these points and sketch this graph which is in the form of a parabola. The curve is in the form of alphabet 'U' with its vertex at the bottom. Now similarly take the square root of x e...

### How To: Compare 2 distributions with the Z-Score formula

This is a video tutorial in the Education category where you are going to learn how to compare 2 distributions with the Z-Score formula. In this example Doug's class has X bar as 71 and a standard deviation of 4. Corey's class has X bar as 68 and a standard deviation of 11. If both Doug and Corey beat the class average and have the same standard score, will Doug have a lower grade than Corey? If both of them have a standard score of 1.5, then Doug will get 77 marks and Corey will get 84.5 mar...

### How To: Factor a trinomial, find the GCF, then group

This lesson describes the method to find the factors of a trinomial, which consists of three terms, by grouping. First of all, factor out the greatest common factor (GCF), and write the reduced trinomial in parentheses. Let the terms of the trinomial be written in order of exponent of the variable. For example, 3(3X2+2X-8) trinomial is written in the order of variable, with 3(GCF) factored out. Now identify the coefficient of the first and last terms, for example in this case, it is 3 and 8. ...

### 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...