What's wrong with these equations?

  • Thread starter kacete
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In summary, the conversation discusses two examples, one involving division by zero and the other using an incorrect mathematical identity. The first example is proven to be incorrect due to division by zero being undefined. The second example is also proven to be incorrect due to the use of an invalid mathematical identity. This conversation highlights the importance of understanding mathematical principles and not being fooled by incorrect proofs.
  • #1
kacete
27
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1=2? -1=1?

First:
Code:
1-1=0
2-2=0

1-1=2-2

1*(1-1)=2*(1-1)

[1*(1-1)]/(1-1)=[2*(1-1)]/(1-1)

[I]1=2[/I]

Second:
Code:
-1=-1

1/-1=-1/1

sqrt(1/-1)=sqrt(-1/1)

sqrt(1)/sqrt(-1)=sqrt(-1)/sqrt(1)

1/i=i/1 note: i=sqrt(-1) complex number

i/(i^2)=i note: i/(i^2) equals 1/i as in 3/9 equals 1/3

i/-1=i note: i^2=-1 complex number

-i=i

i*(-i)=i*(i) note: preserved equality of equation

[I]-1=1[/I]
 
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  • #2
Last edited by a moderator:
  • #3
Now that was simple, thank you. I saw this around and it was messing with me. Guess math can't be tricked. Never would have guessed something similar was already on wikipedia. Thank you!
 

Related to What's wrong with these equations?

1. What are some common mistakes that can be made when solving equations?

Some common mistakes include forgetting to distribute a negative sign, mixing up the order of operations, and miscounting the number of terms in an equation.

2. How can I check if my equation is balanced?

You can check if your equation is balanced by making sure that the same operation is performed on both sides of the equal sign and that the resulting values are equal.

3. Why is it important to show all steps when solving an equation?

Showing all steps helps to ensure that you are following the correct process and can help identify any mistakes that may have been made. It also allows others to follow your work and understand your thought process.

4. What should I do if I get a negative number as my solution?

If you get a negative number as your solution, make sure to check your work and retrace your steps. It is possible that a mistake was made during the solving process.

5. Can I solve an equation without using the order of operations?

No, the order of operations is a fundamental rule in solving equations and must be followed to ensure accuracy. Without following the order of operations, you may arrive at an incorrect solution.

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