Wednesday, February 9, 2011

Binomial Theorem

Binomial= a polygon that has two terms.

Expanding a Binomial:
(x + y)¹ = 1x + 1y
(x + y)² = 1x² + 2xy + 1
(x + y)³ = 1x³ + 3x²y + 3xy² +1
(x + y)⁴ = 1x⁴ + 4x³y + 6x²y² + 4xy³ + 1y⁴

In each expansion there is (n + 1) terms
n= 2 → (2+1) = 3 terms
n= 3 → (3+1) = 4 terms

The power of each term adds up to the power each binomial is added to (n).
For, (x + y) = 1x + 4x³y¹ + 6x²y² + 4x¹y³ + 1y
Powers: (4) (4) (3+1= 4) (2+2=4) (1+3=4) (4)
where n = 4, the sum of powers are 4.


Coefficients of the expansion correspond to the Pascal's Triangle


*During expansion, the x and y have symmetric roles. As the powers of "x" decrease by 1, the powers of "y" increase by 1.
(x + y)⁴ = x(y) + 4x³y¹ + 6x²y² + 4x¹y³ + (x)y


To find the coefficents you can also use the formula:
nCk =


The 2 values next to each others' sum is equal to the number directly below the values. This is the case for all the numbers on Pascal's triangle.

Sunday, February 6, 2011

Geometric Sequences and Series

A Geometric Sequence is the ratios of consecutive terms that are the same.


the number r is the common ratios of the sequence.

The difference between an Arithmaic Sequence and Geometric Sequence
Arithmatic Geometric





Geometric





The sequence whose nth term is 2^n is geometric. For this seqence, the common ratio between consecutive terms is 2.

2,4,8,16...2^n...

4/2= 2


The sum of Geometric Sequences


if r is less that absolute value 1 then the equation is s=a1/1-r

Need more help, follow the link









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Thursday, February 3, 2011

Arithmetic Sequences and Partial Sums

Definition of an Arithmetic Sequence - a sequence whose consecutive terms have a common difference





The common difference (d) is the difference between two consecutive numbers in the sequence.


Example:


4, 8, 11, 14, 17,...

d=3


You can find the nth term of an Arithmetic Sequence by using the equation...
an = dn + c
where c = a1 -d
The equation can also be written as an = d(n-1) + a1
Example:
2, 6, 10, 14, 18
d=4
c=2
an = 4n - 2
The equation for the Sum of a Finite Arithmetic Sequence...

Sn = (n/2)(a1 + an)

You can use this equation to add up the numbers in a Arithmetic Sequence.

Example:

Sn = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 +.....+ 98 + 99 + 100

= (100/2)(1 + 100)
= 50(101)
=5050

You can find a Partial Sum of an Arithmetic Sequence by using the equation for the Sum of a Finite Arithmetic Sequence.

Example:

5, 16, 27, 38, 49,....
Find the 150th term

an = dn + c
a150 = 11(150) - 6
a150 = 1644

S150 = (150/2)(5 + 1644)
S150 = 75(1649)
S150 = 123,675

Sunday, January 30, 2011

Sequence and Series

Definition of Sequence- An infinite sequence is a function whose domain is the set of positive integers. The funciton values



are the terms of the sequence. If the domain of the functioning consists of the first n positive integers only, the sequence is a finite sequence.


Finding the Terms of a sequence





The Fibonacci Sequence: A Recursive Sequence






Definition of Factorials- If n factorial is defined by
As a special case, zero factorial is defined as 0! = 1.



  • 0!=1


  • 1!=1


  • 2!=1 x 2 = 2


  • 3!= 1 x 2 x 3 = 6


Evaluating Factorial Expressions





Definition of Summation Notation- The sum of the first n terms of a sequence is represented by



Where i is called the index of summation, n is the upper limit of summation, and 1 is lower the limit of summation



Sigma Notation for Sums


Monday, January 24, 2011

Systems of Equations

hi.

there are three ways we know how to solve systems of equations


substitution

{x+y = 10, x-y = 4} {equation 1, equation 2}

x=10-y {solve for x in equation 1}

(10-y)-y=4 {substitute 'solution for x in equation 1' into equation 2}
10-2y=4 {simplify}
2y=6
{simplify}

y=3 {solve for y}
x+(3)=10
{plug y into equation 1}

x=7 {solve for x}

solution: (7, 3)



elimination
{x+y = 10, x-y = 4} {equation 1, equation 2}

{x+y=10 {add (or subtract) equations, eliminating one variable}
{x-y=4
-2y=-6
{determine new equation}

y=3 {solve for y}
x+(3)=10 {plug y into equation 1}
x=7 {solve for x}

solution: (7, 3)



graphing

{x+y = 10, x-y = 4} {equation 1, equation 2}

plug both into calculator

find where the graphs intersect each other

solution: (7, 3)


fun stuff i know

bye.

Tuesday, January 18, 2011

Ways to Solve Logarithmic and Exponential Equations

The new way we learned to solve logarithmic equations is exponentiation. Exponentiation acts as an inverse sine, or a square root to make it easier to solve an equation. Just like a square root takes away certain powers, so does exponentiation.

ex.

ex. x=2 b=10 a=100


Monday, January 17, 2011

Exponential Equations

One -to-One Proerties
a^x=a^y if and only if x=y
Logx=Logy if and only if x=y
Example
2^x=32
2^x=2^5
x=5

Inverse Properties
a^logx=x
loga^x=x
Example
e^x=7
lne^x=ln7
x=ln7

Strategies for Solving Exonential and Logarithmic Equations
1. Rewrite the given equation in a form to use the One-to-One properties of exponential or logarithmic functions.
2. Rewrite an exponential equation inlogarithmic form and applly the Inverse property of logarithmic functions.
3. Rewrite a logarithmic equation in exponential formand apply the Inverse Property of exponential functions.

Example
Solve 2(3^(2t-5))-4=11
2(3^(2t-5))-4=11 Write original equation
2(3^(2t-5))=15 Add 4 to each side
3^(2t-5)=15/2 Divide each side by 2
log'3 3^(2t-5)=log'3(15/2) Take log base 3 of each side
2t-5=log'3(15/2) Inverse Property
2t=5+log'3(7.5) Add 5 to each side
t=(5/2)+(1/2)log'3(7.5) Divide each side by 2
t~3.417 Use a calculator