Show that the area of the rectangle is....

  • Context: MHB 
  • Thread starter Thread starter mathlearn
  • Start date Start date
  • Tags Tags
    Area Rectangle
Click For Summary
SUMMARY

The area of a rectangle with length \(x + 1\) and breadth \(x\) is calculated using the variable \(x = -1 \pm \sqrt{11}\). The correct positive value for \(x\) is \(x = \sqrt{11} - 1\), leading to a length of \(\sqrt{11}\) and a breadth of \(\sqrt{11} - 1\). The area is confirmed to be \(11 - \sqrt{11}\). Multiplying by negative values is incorrect as it leads to non-physical dimensions.

PREREQUISITES
  • Understanding of algebraic expressions and variables
  • Knowledge of the properties of rectangles
  • Familiarity with square roots and their implications in geometry
  • Basic skills in mathematical problem-solving
NEXT STEPS
  • Study the properties of rectangles and their area calculations
  • Learn about complex numbers and their applications in geometry
  • Explore algebraic manipulation techniques for simplifying expressions
  • Investigate the implications of negative values in geometric contexts
USEFUL FOR

Students studying geometry, educators teaching algebra, and anyone interested in mathematical problem-solving techniques.

mathlearn
Messages
331
Reaction score
0
There's a rectangle which the length is x+1 and the breadth is x.

X is $$-1\pm\sqrt{11}$$

Show that the area is $$11-\sqrt{11}$$

The workings I have done for far are below.

$$(-1\pm \sqrt{11})*(-1 \pm \sqrt{11} +1) $$

$$(-1\pm \sqrt{11})*( \pm \sqrt{11} ) $$

$$(-1\pm \sqrt{11})*( \pm \sqrt{11} ) $$

$$(-1\pm \sqrt{11})*( \pm \sqrt{11} ) $$

Where have I done wrong ? And the square root of the solution of the area you are asked to show is a negative. A comment here would be appreciated.

Many thanks :)
 
Mathematics news on Phys.org
Measures cannot be negative, so we must have:

$$x=\sqrt{11}-1$$

And so:

$$x+1=\sqrt{11}$$

So, what is the area?
 
MarkFL said:
Measures cannot be negative, so we must have:

$$x=\sqrt{11}-1$$

And so:

$$x+1=\sqrt{11}$$

So, what is the area?

$$(-1+ \sqrt{11})*( + \sqrt{11} ) $$

$$ - \sqrt{11}+ 11 $$

Correct? :)
 
Why would you multiply the expression representing the area by -1?

edit: I see you edited your post. :D
 
MarkFL said:
Why would you multiply the expression representing the area by -1?

edit: I see you edited your post. :D

(Party)(Party)(Happy) Thank you very much MarkFL
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
8K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 10 ·
Replies
10
Views
3K
Replies
2
Views
2K
  • · Replies 21 ·
Replies
21
Views
4K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K