Sunday, October 3, 2010

Quadratic Functions : Circles, Parabola, Elipse, Hyperbola

 Standard form of a Quadratic: ax² + bx + cy² + dy+e=0

If you have an equation like 7x² + 7y²=49 The equation is a circle, because a=c
http://www.webmath.com/cgi-bin/grapher.cgi?answer=y&cgiCall=grapher&getPost=get&param0=3&param1=-&param2=&param3=&param4=-&param5=&param6=&param7=-&param8=&param9=-&param10=&param11=&ymax=10&xmin=-10&xmax=10&ymin=-10&to_plot=circle

If a or c equals 0, the equation is a parabola ( ex: 7x² + 6y= 9)

If a or c have different signs the equation is a hyperbola ( for example: 2x² - 2y²= 8)

If you have an equation like 3x² + 4y²= 24 the equations is an ellipse, because a is not equal to c and the signs are the same


(x-h)² +(y-k)² =r ²  Standard form of a circle

Circle Formula      
 C=πr²                                                     Radius= diameter/2
 A=πr²                                                    Diameter=2r
What is a trinomial perfect square?
(a+b)²

Multiplying Matrices

To determine whether or not matrices can be multiplied you first have to write a dimensions statement.

Example of a dimensions statement:
[ 8 7 ]  [ 4 ]
[ 5  2 ]  [ 1 ]

Dimensions statement:
2 X 2 times 2 X 1



These matrices can be multiplied, so you would multiply row by column.
 Get the sum of the products.
The numbers in yellow tell you that you can multiply the matrices.
The numbers in green tell you the size of the final matrix.

Friday, September 10, 2010

Error Analysis

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBuEjGM4eKWbMitwFPxma5zerReOCdH3uhCqs7NQVEbteXkNzvzQrjhVZlt7FnacxrjhqFZwgAtY3dbl3_eBwK-LLTgmvNolJOaPOOTRxgdI4oBtbHGWNAsQpRRmdvUw7YoKzMObbX31U/s1600/Page_4_Problem_9.jpg

Value of x is going up by 5 and the slope should be 10/5 or 2 not 10/1. Inserting the points, the final equation will be solved.  Y is not equal to 9+10x in the chart

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghNQLHG6o9cST9mDIkoC671psI0OOdb3aafpdUWq7LCEB89yOfl_UI7SiztwvCGmdERKkRfD_W7VRfhQ__XRHMbs138ZvqDdDpfVZnvJSQMY2NJFPdO9wgXChsLlicBsYbFGAHZKPitdg/s1600/Page_8_Problem_16.jpg

To have a point it must try to solve both equations. So (1,2) only solves the first one and not the second one

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHHwE-PSjRlFhywerLEnP98IAKsDXyu9J1-6UrJePYjL1zdcszsMT6jrubOwT9dY2LWwT1t7tcpqFeNrY335sMcFmgUCWE3Yvqsnhk_7yaZyoHS69BYPURJDx7o-UkoCAB1V_cJDxbxY8/s1600/Page_19_Problem_22_and_23.  

 20)shading is correct
  should be dotted line and not solid .
 #21 the solid line is correct, but the shading should be below the line, not above it.

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtHC9QYK3cgnpvPGXc1n3WSjbApC0AIAg5V3L58TfaGgPPpq-M35QTjRAv6yWo_IPc-CDzIabtkn1nLNUIZRdUZYM36kygzU8JwAyAs1_IxSFff-UXf4NF-52CiNV9sEy11RPpYU_NHk4/s1600/Page_21_Problem_20_and_21.jpg

Monday, September 6, 2010

Graphing y=a|x-h|+k


y = a|x - h| + k
Although most books won't call the point (h,k) the vertex (as in quadratics) but it will either be a maximum or minimum value for the absolute value function.
If a > 0 , then (h,k) is the lowest point of the graph.  (opens upward)
If a < 0 , then (h,k) is the highest point of the graph.  (opens downward)

Types of Systems


Case 1
Case
Case 3
graph of intersecting lines
graph of parallel lines
graph with one apparent line




Independent system:
one solution point
Case 2
Case 3
graph of intersecting lines
graph of parallel lines
graph with one apparent line


Independent system:
one solution and
one intersection point
Inconsistent system:
no solution and
no intersection point
Case 3
graph of intersecting lines
graph of parallel lines
graph with one apparent line


Independent  and consistent system:
one solution and
one intersection point
Inconsistent system:
no solution and
no intersection point
Dependent system:
the solution is the
whole line
graph of intersecting lines
graph of parallel lines
graph with one apparent line