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

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

1. 2/3 x 1/8^2
=2/3 x 1/64
=1/96
2nd line onwards is wrong

2. Line 2 - When (1/4 - 1/8)^2 is 1/64
However the answer is (1/4)^2- (1/8)^2 is 3/64

3. Everything was wrong from the second line.. the answer should be 1/96

4. line 2 to 5. (1/4 - 1/8)^2 should be 1/64. therefore the following lines are wrong.

5. The second line is wrong. It should be 2/3 x 1/96, thus all the other answers are wrong too.

6. The mistake was made at Line 2.
The "power" of 2 shouldn't have been brought inside the brackets, causing an error in the answer.
It should be like this:
(1/8) X (1/8)= 1/64

7. the mistake happened at line two.the power should have stayed outside of the brackets.it should have stayed like this:
2/3x[(1/4)x(1/8)}^2

8. The power of 1/4 and 1/8 should be outside the bracket and powered when 1/4 - 1/8

9. In line 2, 1/8 should have been subtracted from 1/4 before square rooting itself instead of square rooting the two fractions first and then subtracting the second fraction from the first one.

10. power should be outside the bracket,not inside in line 2
Correct method:
(1/8) X (1/8)= 1/64
2/3 X 1/64 = 1/96

11. It should be...
1/4-1/8
=2/8-1/8
=1/8
1/8x1/8=1/64
2/3x1/64=1/94