Chap 2: Real Numbers - Spot the Common Mistakes (IV)

Revision Exercise 2 (p52 of Textbook) No. 7(d)

7 comments:

  1. The working in the bracket should be done first then do the power.

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  2. the (1/4-1/8) should be worked out before using the power of two as the answer might vary

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  3. instead of 2/3 x [ (1/4)^2 - (1/8)^2 ], it should be 2/3 x [ (1/8)^2 ]
    we are suppose to do the minusing before the multiplying as the minusing is inside the bracket. so,
    2/3 x {1/4 - 1/8)
    = 2/3 x (1/8^2)
    = 2/3 x 1/4
    =1/6

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  4. It should be 2/3 x (1/4 - 1/8)^2
    =2/3 x (2/8 - 1/8)^2
    =2/3 x 1/8^2
    =2/3 x (1/8 x 1/8)
    =2/3 x 1/64
    =1/96

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  5. we should solve this first:
    = 2/3 x (1/4 - 1/8)^2
    = 2/3 x 1/8^2
    = 2/3 x 1/64
    = 1/96

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  6. we should do 1/4 - 1/8 first before doing to the power of 2.

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  7. Instead of...
    2/3 x (1/4 - 1/8)^2
    =2/3 x ( (1/4)^2 - (1/8)^2 )
    ...
    It should be...
    2/3 x (1/4-1/8)^2
    =2/3 x (1/8)^2
    ...

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