Thursday, August 12, 2010

Online free math

Let us learn online geometry tutor

Online geometry tutors teach the geometric concept to students. Tutors also help to solve their practices problems and clarify their doubts in geometry. In this section we are going to see about the concept of the Geometry. It is used to study about the relationships among shapes and their properties.

Point, line, plane, angle and ray are the topics covered by geometry in this section. Let us see the brief notes about online geometry tutor.
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The point is denoted by a dot. It also denoted by using named a capital letter. A point denotes location only; it has zero size.

A line or straight line can be consideration of as a linked set of infinitely many points. It extends considerably far in two reverse directions.
our next post will be on geometry answers solved

Tuesday, August 10, 2010

Learning reflection definition

Let us learn reflection definition

Reflection is defined as, the ray which passes on a object and get reflected and it forms a reflective ray. This ray is called as mirror image of the original image, which passes through it. The mirror image has the same properties as like the original image.

A triangle is a basic figure and most essential type in the shapes of geometry. It is one of the types of polygons. Triangles are figures which have three sides and three corners, which are line segments. you can also get help with logical mathematical intelligence
The triangles are of many types, they are Right-angled triangle, acute triangle, obtuse triangle, equilateral triangle, isosceles triangle, and scalene triangle. Here we see about the reflective triangles and their properties.

Our next blog will help you with Radical Definition

Wednesday, August 4, 2010

Learning Point slope form

Let us learn about point slope form

The other format for equation of straight line is called as a point slope form .suppose the given is one point and slope then the point slope form can be written as,

General format:
y - y1 = m (x-x1)
Here
(x1,y1) line passes through the point
m represent the slope of the line
Here we are going to learn about how to writ e point slope form and its example problems.
There are many calculators available for solving point slope form.

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Calculate the equation of straight line passes through the point (2, 1) and the slope of the line is 3
Solution:
Given x1=2 and y1=1
Slope (m) =3
We know that point slope form equation y - y1 = m (x-x1)
Substitute th
e slope and point’s value in the above formula we get,

y-1=3 (x-2)
y -1 = 3x -6
Add both sides +1
y– 1+1 = 3x -6 +1
y = 3x-5
Therefore the equation of a line is y = 3x-5

Wednesday, July 21, 2010

How many hours in a year

Do you know how many hours are there in a year

How many hours in a year is nothing but the total hours we have in 1 year. Hours in a year can be calculated by using the multiplication of arithmetic process. We know that 24 hours is equal to 1 day. With the help of this we can find the hours in a year. We know that one normal year is equal to 365 days and one leap year is equal to 366 days.

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Important Terms to Calculate How many Hours in a Year

1 minute = 60 seconds
1 hour = 60 minutes
1 day = 24 hours
1 week = 7 days
1 year = 12 months
1 year = 365 days
1 leap year = 366 days

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Wednesday, July 14, 2010

How to find an Area of a Circle



The area of a circle is a simple shape of Euclidean geometry consisting of those points in a plane which are equidistant from a given point called the center. The common distance of the points of a circle from its center is called its radius.



Finding area of a circle

Example: 1Find the area of the circle with radius 14 meter
Solution:
We know the formula for finding the area of the circle = r2
Here r = 14 meter, = 3.14, substitute r and value in the above formula we get
Area = 3.14 * 142
Area = 3.14 *14*14
Simplify the above we get
Area = 615.44 meter square
Therefore the area of the circle is 615.44 meter 2

More details about area of a circle formula.

Thursday, July 1, 2010

Errors: Absolute and Relative Errors

Absolute Errors

Since no measurement is exact, there will always be the possibility of an error. Numbers are often rounded off to a certain number of significant figures or decimal places, and in such instances an absolute error can be calculated.

If the number 1200 is given to the nearest 100, for example, then the number can be anything between 1150 and 1250. It can therefore be written as 1200 ± 50. In this instance, the absolute error is 50.

In general, if a number is a ± b, then the absolute error is b.

Relative Errors

The absolute error doesn"t really tell us much about how big the error really is. For example, an absolute error of 1000 is very big if the number we are talking about is 3000, but it is small if we are talking about 100 000 000 000. The relative error incorporates the number that we are talking about.

If a number is a ± b, then the relative error is b/a

Example

If 200 is correct to 2 significant figures, what is the relative error?
This can be written as 200 ± 5, since the highest number it could be is 205 and the lowest is 195. The relative error, therefore, is 5/200 = 1/40 = 0.025 .

Percentage Error

Percentage error = relative error × 100

Absolute and Relative Error - Example Problems:

Absolute and relative error - Problem 1:

Student calculates the mass of a sample to be 5.65 g. Actual mass of the sample is 7.75 g. Determine the absolute error and relative error.

Solution:

Experimental calculated Value = 5.65 g

Known Value = 7.75 g

Absolute Error = Experimental calculated value - Known Value
= 5.65 g - 7.75 g
Absolute Error = - 2 g

Relative Error =

Relative Error =

Relative Error = - -0.29629 g.

Absolute and relative error - Problem 2:

Student calculates the mass of a sample to be 6.45 g. Actual mass of the sample is 8.42 g. Determine the absolute error and relative error.

Solution:

Experimental calculated Value = 6.45 g

Known Value = 8.42 g

Absolute Error = Experimental calculated value - Known Value
= 6.45 g - 8.42 g
Absolute Error = - 1.97 g

Relative Error =

Relative Error =

Relative Error = -0.233 g.

Hope you like the above definition and examples of Absolute and Relative Errors.Kindly leave your comments.

Tuesday, June 8, 2010

Logarithms

Introduction

Logarithms were invented by Napier. Before we had calculators, logarithms made calculation easier because they reduced multiplication and divisions to addition and subtraction. These days, logarithms are less important for this purpose.

Logarithms

A logarithm is writen as loga(x) where a is a number called the base. Usually logarithms are written to the base 10 or sometimes base 2 for binary numbers, but it can be any number. If the logarithm is to the base e= 2.71828..., then we call it a natural logarithm because it is the only logarithm base which has a rate of change equal to the thing which is changing. Natural logs are also written, ln(u). The ln comes from the Latin, log naturalis.

Rules of Logarithms

loga(0) is undefined(1)

loga(1) = 0(2)

loga(u v) = loga(u) + loga(v)(3)

loga(u/v) = loga(u) - loga(v)(4)

loga(u)n = n loga(u)(5)

logb(u) = loga(u)/loga(b) - change of base(6)

Where b is the old base, a is the new base, u is the argument of the logarithm.

loga(1/u) = - loga(u) from (2) and (4).(7)

With these rules we can manipulate the exponential functions. Logs are the inverse functions of

Exponential Function

We have seen how to convert a number into a logarithmic number but how about if we are given a logarithm of a number and want to know what the original number was? This is achieved using exponential functions. The exponential function is the inverse function of a logarithmic function.

That is to say, that aloga(u) = u or loga(au)=u

If we have a log to the base 10, the inverse function is 10u.

For natural logarithms, the inverse function is eu or exp(u). In particular, log10(10u) = u

and 10log10(u)= u(8)

ln(eu) = u or eln(u) = u(9)

Example

What is the value of the number the gives the following logs to the base 10:

i) 1, ii) 12, iii) -2, iv) 2.6, v) -5.43

Answers

  1. log10 x = 1
    x=101 = 10
  2. log10 x = 12
    x=1012 = 1x1012
  3. log10 x = -2
    x=10-2 = 0.02
  4. log10 x = 2.6
    x=102.6 = 501.187
  5. log10 x = 12
    x=10-5.43 = 3.71535 x 10-6