Thursday, May 2, 2013

Formulae Of Algebra



Powersx a x b = x (a + b)x a y a = (xy) a
(x a) b = x (ab)
x (a/b) = bth root of (x a) = ( bth (root)(x) ) a
x (-a) = 1 / x a
x (a - b) = x a / x b


Logarithms

y = logb(x) if and only if x=b ylogb(1) = 0
logb(b) = 1
logb(x*y) = logb(x) + logb(y)
logb(x/y) = logb(x) - logb(y)
logb(x n) = n logb(x)

logb(x) = logb(c) * logc(x) = logc(x) / logc(b)

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Polynomial  Identities
(a+b) 2 = a 2 + 2ab + b 2
(a+b)(c+d) = ac + ad + bc + bd
a 2 - b 2 = (a+b)(a-b) (Difference of squares)
a 3 (+-) b 3 = (a (+-) b)(a 2(-+) ab + b 2(Sum and Difference of Cubes)
x 2 + (a+b)x + AB = (x + a)(x + b)

if ax 2 + bx + c = 0 then x = ( -b (+-)sqrt(b 2 - 4ac) ) / 2a (Quadratic Formula)

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Closure Property of Addition
Sum (or difference) of 2 real numbers equals a real number
Additive Identity

a + 0 = a
Additive Inverse

a + (-a) = 0
Associative of Addition

(a + b) + c = a + (b + c)
Commutative of Addition

a + b = b + a
Definition of Subtraction

a - b = a + (-b)

Closure Property of Multiplication

Product (or quotient if denominator (!=)0) of 2 reals equals a real number
Multiplicative Identity

a * 1 = a
Multiplicative Inverse

a * (1/a) = 1     (a (!=) 0)
(Multiplication times 0)

a * 0 = 0
Associative of Multiplication

(a * b) * c = a * (b * c)
Commutative of Multiplication

a * b = b * a
Distributive Law

a(b + c) = ab + ac
Definition of Division

a / b = a(1/b)
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CONIC SECTION
circle conicellipse conicparabola conichyperbola conic
Circle
graph circle (horiz.)
Ellipse (h)
graph ellipse (horiz.)
Parabola (h)
graph parabola (horiz.)
Hyperbola (h)
graph hyperbola (horiz.)
Definition:
A conic section is the intersection of a plane and a cone.
Ellipse (v)
graph ellipse (vert.)
Parabola (v)
graph parabola (vert.)
Hyperbola (v)
graph hyperbola (vert.)

By changing the angle and location of intersection, we can produce a circle, ellipse, parabola or hyperbola; or in the special case when the plane touches the vertex: a point, line or 2 intersecting lines.
point conicline conicdouble line conic
Point
graph point conic
Line
graph line conic
Double Line

The General Equation for a Conic Section:
Ax2 + Bxy + Cy2 + Dx + Ey + F = 0

The type of section can be found from the sign of: B2 - 4AC
If B2 - 4AC is...then the curve is a...
 < 0ellipse, circle, point or no curve.
 = 0parabola, 2 parallel lines, 1 line or no curve.
 > 0hyperbola or 2 intersecting lines.

The Conic Sections. For any of the below with a center (j, k) instead of (0, 0), replace each x term with (x-j) and each y term with (y-k).
CircleEllipseParabolaHyperbola
Equation (horiz. vertex):x2 + y2 = r2x2 / a2 + y2/ b2 = 14px = y2x2 / a2 - y2 / b2= 1
Equations of Asymptotes:y = ± (b/a)x
Equation (vert. vertex):x2 + y2 = r2y2 / a2 + x2/ b2 = 14py = x2y2 / a2 - x2 / b2= 1
Equations of Asymptotes:x = ± (b/a)y
Variables:r = circle radiusa = major radius (= 1/2 length major axis)
b = minor radius (= 1/2 length minor axis)
c = distance center to focus
p = distance from vertex to focus (or directrix)a = 1/2 length major axis
b = 1/2 length minor axis
c = distance center to focus
Eccentricity:0c/a1c/a
Relation to Focus:p = 0a2 - b2 = c2p = pa2 + b2 = c2
Definition: is the locus of all points which meet the condition...distance to the origin is constantsum of distances to each focus is constantdistance to focus = distance to directrixdifference between distances to each foci is constant
Related Topics:Geometry section on Circles
aAlgebraic  Graph
  
  
Conic Sections
(see also Conic Sections)
Point

x^2 + y^2 = 0
Circle

x^2 + y^2 = r^2
Ellipse

x^2 / a^2 + y^2 / b^2= 1
Ellipse

x^2 / b^2 + y^2 / a^2= 1
Hyperbola

x^2 / a^2 - y^2 / b^2= 1
Parabola

4px = y^2
Parabola

4py = x^2
Hyperbola

y^2 / a^2 - x^2 / b^2= 1
For any of the above with a center at (j, k) instead of (0,0), replace each x term with (x-j) and each y term with (y-k) to get the desired equation.

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