Sunday, March 7, 2010

Alicia's Reflection #29

Okay so all we have been doing since we watched the movie for Flatland is take our Chapter tests all the way back to chapter 1. Im just going to review some sequences and series for the upcoming chapter tests.

arithmetic sequences have addition and subtraction:

tn=t1+(n-1)d

> find the 28th term.

t28=3+(27)(2)
t28=3+54
t28=57

a geometric sequence is a sequence that has multiplication and division:

tn=t1*r^(n-1)

>find the 10th term

t10= 2*2^9
t10= 2*512
t10= 1024


Example: Find the formula for the nth term of the arithmetic sequence. 3,5,7

tn=3+(n-1)(2)
tn=3+2n-2
tn=1+2n

Example: Find the formula for the nth term of the sequence. 3,4.5,6.75

r=4.5/3=3/2

6.75/4.5=3/2

tn=3x(3/2)^n-1
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1 comment:

  1. AmyMarch 13, 2010 at 1:53 PM

    Cautions:

    **you can't divide trig functions to cancel them

    Example:

    2 cos (theta) / cos (theta) = cos² (theta)/ cos (theta)

    **but you can move everything to one side & factor out a trig function
    **or divide by a trig function to create a new one:

    Example:

    sinxtanx = 3sinx

    sinxtanx - 3sinx = 0

    sinx (tanx - 3) = 0

    sinx = 0

    x = sin^-1 (0)

    x = 0, pie, 2pie

    tanx -3 = 0

    tanx = 3

    x = tan^-1 (3)

    x= 71.565 pie/180, 257.565 pie/180

    ReplyDelete

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