Thursday, September 8, 2016

hw #1-3 Who knew? Parentheses are our friends!

hw #1-3
pg 20 #1-8 ALL, #9-35 ODD, 46, 47

Hand-in Assignment - pg 14 from section #1-2
As discussed in class, evaluate the expressions based on the substitutions detailed below, NOT the positive numbers provided in the problem... show ALL WORK!!
#47 use m=-2, n=-3
#49 use p=-5; q=-3

12 comments:

  1. On question 17 page 20 I was confused on how to get a square root of a decimal so I checked the back of the book for the answer. I know the answer is 1.4 but i don't know how to get there and/or show my work for it.

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    1. The technique for this problem would be to find the square root of 196... it is 14.

      Since 14^2 = 196, it follows that 1.4^2 = 1.96
      Similarly,
      4^2 = 16 so .4^2 = .16
      12^2=144 so 1.2^2 = 1.44
      25^2 = 625 so 2.5^2 = 6.25

      For the most part, you will be using a calculator to find square roots. I am going to suggest that you memorize some common square roots. We'll talk about it in class.

      You should also be able to estimate square roots... for example,

      Given that 20^2 = 400 and 21^2 = 441 and 25^2 = 625
      you should be able to estimate the following:

      22^2 = ??
      Sqrt(600) = ??

      See if you can estimate these before reading on...

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    2. I would expect that, given the above information, you could estimate that
      22^2 is between 441 and 625, probably closer to 441 and somewhere around 500 (it's actually 484)
      Sqrt(600) is probably between 24 and 25, since 25^2 = 625
      (use a calculator to find that Sqrt(600) = 24.494897...

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  2. Thank you Mr.C for the explanation it helped and I did practice some basic square roots and practiced estimating them too. Thanks for the help :)

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  3. On question 33 pg 20,I had to find what subcategory(s) 17/4573 (fraction) belonged to (rational, integer, whole numbers, natural numbers or irrational numbers). I first reduced it to 1/269 which I felt would be a little easier to work with. I thought it was an irrational number because I didn't think 1/269 terminated but like Ryan, I checked the back of the book to find that it was rational. How would you solve this question?

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    1. Great question!!

      A RATIOnal number can be written as a RATIO of two integers... 1 is an integer and 269 is an integer... so 1/269 is rational, just like 1/2, 1/4 or 1/16.

      See the definition of "rational number" at the top of pg 18.

      The only irrational numbers of any consequence that you will come into in this class are as follows
      1) pi (i.e. 3.14159..... yada yada)
      2) square roots of non-perfect squares i.e. the SQRT(2), SQRT(3), SQRT(5) are all IRRATIONAL NUMBERS

      The SQRT(4)=2, SQRT(9)=3, SQRT(16)=4, etc...

      The SQRT(1.96)=1.4 (see Jake's question above)

      This can be a tough concept for beginning algebraticians... I don't focus on it too much early on... it is a topic we will hit from time to time as the year goes on and it will begin to sink in.

      Thanks for asking... many others have the same question... check out the CONCEPT SUMMARY on page 18 for some quick help... I'm gonna have you copy that into your toolkit real soon.

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    2. Thanks for explaining the question! I totally get it now and for any future questions similar to this will remember the method ^.

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    3. Thank you for the feedback... it helps me help you AND everybody else...

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  4. SO we can use calculator for some questions?

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  5. The non rational tip was really helpful. I was so confused between irrational and rational. Thanks for explaining the difference because the definition in the book wasn't helping. I'm sure I got some wrong with that on the homework, but now I know for next time.

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  6. For the hand in, for the procedural algebra part, is all we are supposed to do, for example, 5 (3+x), show the arrows and write below it 15+5x? Or are we supposed to use a rectangle and split up the numbers on it and add all the numbers down in a row? Or something else?

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