- #1
Saladsamurai
- 3,020
- 7
Homework Statement
Here we go. Write the following with at least one less absolute value symbol:
(ii) |(|a+b| - |a| - |b|)|
(iii) |(|a + b| + |c| - |a + b + c|)|
(iv) |x2 - 2xy + y2|
Homework Equations
12 Properties of Numbers.
The Attempt at a Solution
Let's just look at (ii) for now since I am getting all flustered with it:
|(|a+b| - |a| - |b|)|
There are 2 potential abs value symbols that could be dealt with:
1) I could try to show that the quantity |a+b| - |a| - |b| ≥ 0 and the outermost symbols could be dropped.
OR
2) Try to show that -|a|-|b| = -|a+b| and re-write the original expression as |(|a+b| - |a + b|)|
Either way is a pain. It seems like there are so many 'cases' to test. Am I correct in saying that I would need to test all of the following cases?
I. a = b > 0
II. 0 < b < a
III. 0 < a < b
IV. a < 0 < b where |a| < |b|
V. b < 0 < a where |b| < |a|
VI. a < 0 < b where |b| < |a|
VII. b < 0 < a where |a| < |b|
VIII. a = b = 0
IX. a = b < 0
Am I overkilling here? Are any of these equivalent? I am thinking "no" because its subtraction involved ...