Monday, March 7, 2011
Polynomial Functions
A polynomial function is one that can be written in the form
anx + an-1xn-1+…+a3x3+a2x2 + a1x+ a0
Where n is an non negative integer, x is a variable, and each of a0,a1,a2,…an is a constant called a coefficient.
Find the domain of each rational function
1) f(x) = 1/x2
The domain of f(x) = 1/x2 is the set of all real numbers except x = 0 because the denominator is 0 when x=0, making the fraction undefined
2) g(x) = x2 + 3x + 1/x2-x-6
The domain of g(x) = x2 + 3x + 1/x2-x-6 is the set of all real numbers except the solutions of x2-x-6=0. Because x2-x-6 factors into (x+2)(x-3), the solutions to x2-x-6=0 are x=-2 and x=3. Therefore, the domain of g is the set of all real numbers except x = -2 and x=3
Real Functions:
Synthetic Division:
Inequalities
Inequalities
-Range of values for a solution.
Solving a compound linear inequality:
Example:
2<3x+5<2x+11
A solution of 2<3x+5<2x+11 is any number that is a solution of both of the following inequalities.
2<3x+5 and 3x+5 <2x +11
each of these inequalities can be solved by the principles listed above.
2 - 5 <3x 3x - 2x< 11- 5
-3<3x x<6
-1<x
the solutions are all real numbers that satisfy both -1<x and x<6, that is -1<x<6. Therefore, the solutions are the numbers in the interval [-1,6).
Example:
4 < 3-5x<18
When a variable appears only in the middle of a compound inequality the process can be streamlines by performing any operation on each part of the compound inequality.
4<3-5x<18
1<-5x<15
-1/5> x > -3
Intervals are usually written from the smaller to the larger, so the solution to the compound inequality is -3<x<-1/5
The solution of a compound inequality is the interval (-3,-1/5)
Kahn Academy:
http://www.khanacademy.org/video/algebra--solving-inequalities?playlist=Algebra
http://www.khanacademy.org/video/quadratic-inequalities?playlist=Algebra
-Range of values for a solution.
Solving a compound linear inequality:
Example:
2<3x+5<2x+11
A solution of 2<3x+5<2x+11 is any number that is a solution of both of the following inequalities.
2<3x+5 and 3x+5 <2x +11
each of these inequalities can be solved by the principles listed above.
2 - 5 <3x 3x - 2x< 11- 5
-3<3x x<6
-1<x
the solutions are all real numbers that satisfy both -1<x and x<6, that is -1<x<6. Therefore, the solutions are the numbers in the interval [-1,6).
Example:
4 < 3-5x<18
When a variable appears only in the middle of a compound inequality the process can be streamlines by performing any operation on each part of the compound inequality.
4<3-5x<18
1<-5x<15
-1/5> x > -3
Intervals are usually written from the smaller to the larger, so the solution to the compound inequality is -3<x<-1/5
The solution of a compound inequality is the interval (-3,-1/5)
Kahn Academy:
http://www.khanacademy.org/video/algebra--solving-inequalities?playlist=Algebra
http://www.khanacademy.org/video/quadratic-inequalities?playlist=Algebra
Arithmetic and Geometric Sequences
-An arithmetic sequence has a constant difference and can be expressed as a line.
-A geometric pattern is a not linear, it is exponential.
Arithmetic Sequence:
In an arithmetic sequence {Un}
Un=Un-1+d
And for some constant d and all n>2
Example:
If {Un} is an arithmetic sequence with U1= 3 and U2 = 4.5 as its first two terms,
a) a) find the common difference
b) b) write the sequence as a recursive function
c) c) give the first seven terms of the sequence
Solution:
A) a) the sequence is arithmetic and has a common difference of U2-U1 = 4.5 - 3 = 1.5
B) b) the recursive function that describes the sequence is U1 = 3 and Un-1 + 1.5 for n>2
C) c) the first seven terms are 3, 4.5, 6, 7.5, 9, 10.5 and 12
Geometric Sequence:
In a geometric sequence {Un}
Un=RUn-1
For some U1 and some nonzero constant r and all n>2
Example:
Is the following sequence geometric? If so, what is the common ratio? Write each sequence as a recursive function.
{3,9,27,81...}
The sequence is geometric with a common ratio of 3.
U2/U1 = 9/3 = 3
U3/U2 = 27/9 = 3
U4/U3 = 81/27 = 3
Because each term is obtained by multiplying the precious term by 3, the sequence may be denoted as a recursive function
U1 = 3 and Un=3Un-1 for n>2
Kahn Academy:
http://www.khanacademy.org/video/sequences-and-series--part-1?playlist=Calculus
Kahn Academy:
http://www.khanacademy.org/video/sequences-and-series--part-1?playlist=Calculus
Using Quadratic Formula and Completing the Square
Ax^2 + Bx + C = 0
x^2 +( b/a)x = -(c/a)
1. 1. x^2 +(b/a) + (b/a)^2 = (b/2a)^2 – (c/a)
2. 2, (x + (b/2a)^2) = (b/2a)^2 – (c/a)
3. 3. x +(b/2a) = + or - (b^2/4a^2)-(c/a)
4. 4. x = + or - Square Root b^2/4a^2 – c/a
5. 5. x = -b/2a + or - Square Root b^2-4ac/4a^2
6. 6. x = -b/2a + or - Square Root b^2-4ac/2a
7. 7. x = -b + or - Square Root b^2 – 4ac/2a
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