When should the plus/minus sign be used when dealing with square roots?

Click For Summary
SUMMARY

The discussion centers on the use of the plus/minus sign (±) when solving equations involving square roots, specifically in the context of the equation x² = 9. Participants argue that while the conventional solution is x = ±3, this notation can lead to confusion regarding the uniqueness of solutions. The consensus is that the notation ± is an "abuse of notation" that simplifies the expression but does not accurately reflect the underlying mathematical principles. The discussion emphasizes that the square root of a variable squared should be treated with caution, as it can lead to multiple valid solutions.

PREREQUISITES
  • Understanding of basic algebraic principles, including solving quadratic equations.
  • Familiarity with the properties of square roots and absolute values.
  • Knowledge of mathematical notation, particularly the use of the plus/minus sign (±).
  • Ability to analyze logical statements and implications in mathematical contexts.
NEXT STEPS
  • Study the properties of absolute values and their relation to square roots.
  • Learn about the implications of using logical notation in mathematical proofs.
  • Explore the concept of multiple solutions in quadratic equations and their representations.
  • Review common mathematical notations and their proper usage in equations.
USEFUL FOR

Students transitioning from basic algebra to more advanced mathematics, educators teaching algebraic concepts, and anyone interested in understanding the nuances of mathematical notation and solution representation.

  • #31
Dr. Mirrage said:
So, then the only question I still have is when should I use the plus/minus sign?
When it makes things easier -- when it makes it easier for you to (correctly) solve a problem, when it makes it easier for you to explain something, and so forth.

If you don't find it makes things easier, then don't use it.
 

Similar threads

  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
1K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 18 ·
Replies
18
Views
5K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K