The ongoing cycle

MagMyPic

ischoolsjabaclao — Fri, 22 Jan 2010 04:51:12 +0000

Create Fake Magazine Covers with your own picture at MagMyPic.com

MagMyPic

ischoolsjabaclao — Fri, 22 Jan 2010 04:34:49 +0000

Create Fake Magazine Covers with your own picture at MagMyPic.com

Brief History

ischoolsjabaclao — Sat, 21 Nov 2009 02:47:11 +0000

Brief History

November 21, 2009 at 2:43 am | In 1 | Leave a Comment | Edit this post

Circle’s history goes in two directions at once. It goes backwards as it goes forwards because circle has neither a beginning nor an end, it is just one continuous line.The concept of the circle is ubiquitous. It can be described mathematically, represented physically, and employed technologically. We drive cars that go on round tires, we operate our laundry machines with quarters, and we unscrew our ketchup bottle caps. The circle is an elegant, abstract form that has been transformed by humans into a vast array of tangible, and practical applications.

The study of the circle goes back beyond recorded history. The invention of the wheel is a fundamental discovery of properties of a circle. The greeks considered the Egyptians as the inventors of geometry. The scribe Ahmes, the author of the Rhind papyrus, gives a rule for determining the area of a circle which corresponds to π = ²⁵⁶/₈₁ or approximately 3.16.The first theorems relating to circles are attributed to Thales, the first known Greek philosopher, scientist and mathematician. He is credited with five theorems of elementary geometry around 650 BC. Book III of Euclid’s Elements deals with properties of circles and problems of inscribing and escribing polygons.

One of the problems of Greek mathematics was the problem of finding a square with the same area as a given circle. Several of the ‘famous curves’ in this stack were first studied in an attempt to solve this problem. Anaxagoras in 450 BC is the first recored mathematician to study this problem. The problem of finding the area of a circle led to integration. For the circle with formula given above the area is πa² and the length of the curve is 2πa. The pedal of a circle is a cardioid if the pedal point is taken on the circumference and is a limacon if the pedal point is not on the circumference. The caustic of a circle with radiant point on the circumference is a cardioid, while if the rays are parallel then the caustic is a nephroid. Apollonius, a Greek mathematician known as ‘The Great Geometer’ showed effectively that the bipolar equation r = kr‘ represents a system of coaxial circles as k varies. In terms of bipolar equations mr² + nr‘² = c² represents a circle whose centre divides the line segment between the two fixed points of the system in the ratio n to m. His works had a very great influence on the development of mathematics and his famous book Conics introduced the terms parabola, ellipse and hyperbola.in about 240 BC,

Brief History

ischoolsjabaclao — Sat, 21 Nov 2009 02:43:42 +0000

Let’s sing a circle song!

ischoolsjabaclao — Sat, 21 Nov 2009 01:43:10 +0000

You want to listen?

>Circle song 1

>Circle song 2

This video gives us an awareness that circle has no end, all of us travels on it without knowing our destinations. We are just continuing our journey to achieve all our goals and dreams in life. It will also serve as your tool to learn how to sing through Mathematics, so enjoy singing!!!!

SOURCE: www.youtube.com

>thanks to youtube!

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ischoolsjabaclao — Sat, 21 Nov 2009 01:38:32 +0000

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Brain Wave

ischoolsjabaclao — Sat, 21 Nov 2009 01:32:47 +0000

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Arc

ischoolsjabaclao — Fri, 20 Nov 2009 02:00:39 +0000

What comes in your mind as you hear the word arc? There are lots of definition for an arc isn’t it? but what I am going to share to you is all about arc of a Circle. Strictly speaking, an arc could be a portion of some other curved shape, such as an ellipse, but it almost always refers to a circle.Arc is portion of the circumference of a circle it has a number of definitions in Mathematics, but in general, arc is a smooth curve joining two points, the length of an arc is the what we called “Arc length”. Arc is measured in two ways: as the measure of a central angle or as the length of the arc itself. The arc of a circle is defined or classified as the major arc and minor arc.

Central Angle

ischoolsjabaclao — Fri, 20 Nov 2009 01:42:42 +0000

The angle subtended at the center of a circle by two given points on the circle.Central angle is an angle formed by two rays from the center of a circle, with the center forming the vertex. A central angle is an angle whose vertex is the center of a circle, and whose sides pass through a pair of points on the circle, thereby subtending an arc between those two points whose angle is (by definition) equal to the central angle itself. It is also known as the arc segment’s angular distance.

There are several different angles associated with circles. Perhaps the one that most immediately comes to mind is the central angle. It is the central angle’s ability to sweep through an arc of 360 degrees that determines the number of degrees usually thought of as being contained by a circle. The Central Angle Theorem states that the measure of inscribed angle is always half the measure of the central angle It also says that the measure of the minor arc is equal to the measure of a central angle.

Inscribed Angle

ischoolsjabaclao — Fri, 20 Nov 2009 01:25:32 +0000

Definition: The angle subtended at a point on the circle by two given points on the circle.

Try this Drag any orange dot. Note that when moving the point P, the inscribed angle is constant while it is in the major arc formed by A,B.

(If there is no image below, see support page.)

Java plug-in Version 1.4 or later required.

Given two points A and B, lines from them to a third point P form the inscribed angle ∠APB. As you drag the point P above, notice that the inscribed angle is constant. It only depends on the position of A and B.

The inscribed angle is only defined for points on the major arc (the longest path around the circle between the two given points). In the figure above, if you drag P around into the shorter (minor) arc it will be undefined.

Formula for inscribed angle

If you know the length of the minor arc and radius, the inscribed angle is:

where:
L is the length of the minor (shortest) arc AB
R is the radius of the circle
π is Pi, approximately