Can Absolute Value Inequalities Prove This Expression?

In summary, absolute value is the distance from zero on the number line and is always positive. To prove an absolute value equation, both positive and negative values must be substituted and solved. Absolute value and modulus are similar but have slightly different definitions. The properties of absolute value can be used to solve equations, but common mistakes include forgetting to consider both positive and negative solutions, misapplying the properties, and failing to simplify the equation before solving.
  • #1
Andrax
117
0

Homework Statement


we know that |a| < c and |bl < c
prove that : (la+bl + la-bl)/2 < c






The Attempt at a Solution


all I've gotten to so far is this : la+bl < 2c
lal + lbl < 2c
we have : la+bl < lal+lbl
then la+bl < 2c
i need to prove that la-bl < 0.?
also by squaring all i gotten so far is (la+bl + la-bl)/2 < 2c...
 
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  • #2
Hi Andrax! :smile:
Andrax said:
we know that |a| < c and |bl < c
prove that : (la+bl + la-bl)/2 < c

If they're complex, it's not true.

If they're real, then just try the 4 different ± possiblities, :wink:
 

1. What is the definition of absolute value?

The absolute value of a number is its distance from zero on the number line. It is always positive and is represented by two vertical bars surrounding the number, such as |3|.

2. How do you prove an absolute value equation?

To prove an absolute value equation, you must show that the equation holds true for both the positive and negative values of the variable. This can be done by substituting the positive and negative values into the equation and solving for each case.

3. What is the difference between absolute value and modulus?

Absolute value and modulus are often used interchangeably, but they have slightly different definitions. Absolute value is the distance from zero on the number line, while modulus is the numerical value of a number without its sign.

4. Can you use the properties of absolute value to solve equations?

Yes, the properties of absolute value can be used to solve equations. These properties include the distance property, which states that the absolute value of a sum is equal to the sum of the absolute values, and the multiplication property, which states that the absolute value of a product is equal to the product of the absolute values.

5. What are some common mistakes when solving absolute value equations?

Some common mistakes when solving absolute value equations include forgetting to consider both the positive and negative solutions, incorrectly applying the properties of absolute value, and not simplifying the equation correctly before solving for the variable.

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