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May 17, 2024, 06:53:51 pm

Author Topic: Methods ain't my cup of tea :S  (Read 942 times)  Share 

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elaine

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Methods ain't my cup of tea :S
« on: February 23, 2008, 12:59:07 pm »
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I'm having trouble with my methods- could someone help with a couple of questions? I'd be so grateful!
Oh and sorry if they're very amateurish lol.

1. Find a and b
A(x+3) + B(x+2) = 4x +9

2. Find A, B, C
x^3 - 9x^2 +27x - 22 = A(x +B)^3 for all Real Numbers

3. Divide x^4 - 9x^3 +25x^2 -8x -2 by x^2 - 2

4.  Find inverse and state the domain h(x)= 5 - 2/(x-6)^3

5. State the sequence of transformation to transform the graph of the first graph into the graph of the second

y= 2/(3-x), y= 1/(x)

Thank you so much :)
« Last Edit: February 23, 2008, 01:02:14 pm by elaine98 »
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dcc

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Re: Methods ain't my cup of tea :S
« Reply #1 on: February 23, 2008, 01:35:14 pm »
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1. Simultaneous equations & equating coefficients:





We can equate coefficients here and we get a pair of simultaneous equations:

&

:.



Substituting back in, you get

2. Calculus (or expansion if you like):

I assume you meant , because otherwise this equation doesn't make alot of sense :P

This is the form of a cubic in point-of-inflection form, so using calculus to find this point:





Let :







So we have as a location for our point of inflection:

Substituting x = 3 into original equation:



so we have the pair:

Now remembering our general cubic form:

, where h is the x-coordinate of the point of inflection and k is the y-coordinate. a is the dilation factor (in this case, it is 1, because in the LHS the term has a coefficient of 1

so

:.

3: Polynomial Long Division:


           



        

                  

              

                           

                         

                      Remainder:

Remebering our form for long division:



Where , , & :



4.  Inverse



This function is one-to-one, so it will have an inverse:

To find an inverse, just swap around the x & y variables then rearrange the equation:











Now for this equation to not have a divide-by-zero, you will need the following domain:

Domain: (which is the range of our original function)
« Last Edit: February 23, 2008, 03:38:17 pm by dcc »

iamdan08

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Re: Methods ain't my cup of tea :S
« Reply #2 on: February 23, 2008, 02:13:46 pm »
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Question 5



1) Dilation by a factor of in the x axis yields:



2) reflection in the y axis yields:



3) translation of 3 units in the positive x-direction yields:




« Last Edit: February 23, 2008, 02:19:06 pm by iamdan08 »
2007-08 VCE - Accounting, Texts & Traditions, Methods, Chem, Physics, Lit
         
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elaine

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Re: Methods ain't my cup of tea :S
« Reply #3 on: February 26, 2008, 10:14:13 pm »
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thank you guys so much! wow those explanations help a lot :)
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