Conic Sections

Introduction:

Algebra is the one of the most important chapter in mathematics subject. Here the Conic section is one of the topics in algebra chapter. In mathematics a conic section (or just conic) is a curve obtained by intersecting a cone (more precisely, a right circular conical surface) with a plane. In analytic geometry, a conic may be defined as a plane algebraic curve of degree 2. The conic sections were named and studied as long ago as 200 BC.

Conic Sections:

Conic section is generally defined as intersection of a plane and a cone, it will  depend on How the plane is oriented, the curve will be one conic sections. Or a conic section is a curve formed by the intersection of a cone with a plane.
 Four types of conic sections are there,

• Circle,
• Parabola,
• Ellipse, and
• Hyperbola.

Conics: Ellipses: Introduction

Conics: Ellipses: Introduction
An ellipse, informally, is an oval or a "squished" circle. In "primitive" geometrical terms, an ellipse is the figure you can draw in the sand by the following process: Push two sticks into the sand. Take a piece of string and form a loop that is big enough to go around the two sticks and still have some slack. Take a third stick, hook it inside the string loop, pull the loop taut by pulling the stick away from the first two sticks, and drag that third stick through the sand at the furthest distance the loop will allow. The resulting shape drawn in the sand is an ellipse.
Each of the two sticks you first pushed into the sand is a "focus" of the ellipse; the two together are called "foci" (FOH-siy). If you draw a line in the sand "through" these two sticks, from one end of the ellipse to the other, this will mark the "major" axis of the ellipse. The points where the major axis touches the ellipse are the "vertices" of the ellipse. The point midway between the two sticks is the "center" of the ellipse.

Equation of Ellipse with Standard Positions

Equation	X2/a2+y2/b2=1, a > b	X2/a2+y2/b2=1, a <>
Centre	(0,0)	(0,0)
Coordinate of centre.	(a,0),(-a,0)	(0,b),(0,-b)
Length major axis	2a	2b
Length of minor axis	2b	2a
Equation of major axis	Y = 0	X = 0
Equation of minor axis	X = 0	Y = 0
Equation of directrix	X = ± a/e	Y = ± b/e
Eccentricity Latus rectum	‘e’ = √(1-b2/a2) 2b2/a	‘e’ = √(1-a2/b2) 2a2/b
Focal distance	a ± ex	b ± ey
Coordinates of foci.	(ae , 0), (- ae , 0)	(0 , be). (0 , - be)

Hope you like the above Equation of Ellipse with Standard Positions Expression
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Translating Word Problems

Translating Word Problems: The first step to effectively translating and solving word problems is to read the problem entirely. Don't start trying to solve anything when you've only read half a sentence. Try first to get a feel for the whole problem; try first to see what information you have, and what you still need.

The second step is to work in an organized manner. Figure out what you need but don't have, and name things. Pick variables to stand for the unknows, clearly labelling these variables with what they stand for. Draw and label pictures neatly. Explain your reasoning as you go along. And make sure you know just exactly what the problem is actually asking for. You need to do this for two reasons:
The third step is to look for "key" words. Certain words indicate certain mathematical operations. Below is a partial list.
Addition- increased by more than combined, together total of sum added to
Subtraction- decreased by minus, less difference between/of less than, fewer than
Multiplication- of times, multiplied by product of increased/decreased by a factor of (this type can involve both addition or subtraction and multiplication!)
Division- per, a out of ratio of, quotient of percent (divide by 100)
Equals- is, are, was, were, will be gives, yields sold for

Translating Word Problems: Examples

• Translate "the sum of 8 and y" into an algebraic expression.
  This translates to "8 + y"

• Translate "4 less than x" into an algebraic expression.
  This translates to "x – 4"
  
  Remember? "Less than" is backwards in the math from how you say it in words!

•  Translate "x multiplied by 13" into an algebraic expression.
  This translates to "13x"

• Translate "the quotient of x and 3" into an algebraic expression.
  This translates to " x/3"

• Translate "the difference of 5 and y" into an algebraic expression.
  This translates to "5 – y"

• Translate "the ratio of 9 more than x to x" into an algebraic expression.
  This translates to "(x + 9) / x"

• Translate "nine less than the total of a number and two" into an algebraic expression, and simplify.
  This translates to "(n + 2) – 9", which then simplifies to "n – 7"
  
  Here are some more wordy examples:

• The length of a football field is 30 yards more than its width. Express the length of the field in terms of its width w.
  
  Whatever the width w is, the length is 30 more than this. Recall that "more than" means "plus that much", so you'll be adding 30 to w.

         The expression they're looking for is "w + 30".

Hope you like the above example of Translating word Problems
Please leave your comments, if you have any doubts.