Monday, November 9, 2009

post 12

So Monday and Tuesday we reviewed stuff we didn't understand so we could be ready for the tests on wednesday and thursday. i stilll have trouble w/ most of it. our testw as on everything we did this whole y ear. i understand some of it now.

im not really good at lookin at a graph and finding its horizontal tangents and whether or not it is concave up or down. and i dont know what its derivative is supposed to look like and i'd like some hlep w/ this :)

Another thing I still can't seem to understand is optimization and angles of elevation. I don't know what my problem is becuase i dont know it from teh beginning. i just get so confused in what im trying to do. i know the steps well enough its just actually doin the steps that gets me.

So after the tests we found out that as a whole we suck at limits.
limit rules:
1. If the degree of the top equals the degree of the bottom the answer is the top coefficient over the bottom coefficient.
For example, lim x>infinity x^5/4x^5 + 2 = 1/4
2. If the degree of the top is greater than the degree of the bottom, the answer is + or - infinity
Ex: lim x>infinity x^5 -3x^1/ x + 1 = infinity
3. If the degree of the top i less than the degree of the bottom, the answer is 0.
Ex: lim x>infinity x/x^8 + 2 = 0

the rules are pretty easy.

Linearization is something i dont really think i know too well. so if anyone wants to help w/ all this i'd appreciate it ;)

3 comments:

  1. Linearization
    any time we see the word APPROXIMATE we will be using linerarization.
    For example:
    Approximate the tangent line to y=(x)^2 at x=5
    that means that dy/dx is 2x
    so when we plug in 5 for x we get 2(5) which is 10. 10 is our slope!. Now we will take the original and plug in 5 for x giving us y=(5)^2, so that's y=25.
    Since the equation for Linerarization is f(x) = f(c) + f'(c)*(x-c) we will plug in what we have into the equation. we know that f(c)=25...f'(c)=2...and c=5 so when we plug in we get>>>> f(x)=25+2(x-5)

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  2. the steps for linearization to go with ellie's explanation above are
    1. Pick out the equation
    2. f(x)+f`(x)dx
    3. Figure out your dx
    4. Figure out your x
    5. Plug in the dx and x you get

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  3. In linearization the key word is approximate.

    The rules for linerzation are:
    1. identify an equation
    2. f(x)+f'(x)dx is the equation you use
    3. determine dx
    4. determine x
    5. plug dx and x into the equation

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