Below is for those who are still interested in Algebra:
For the rest, please skip.
The Fallacious Proof:
- Step 1: Let a=b.
- Step 2: Then ,
- Step 3: ,
- Step 4: ,
- Step 5: ,
- Step 6: and .
- Step 7: This can be written as ,
- Step 8: and cancelling the from both sides gives 1=2.
See if you can figure out in which step the fallacy lies. When you think you've figured it out, click on that step and the computer will tell you whether you are correct or not, and will give an additional explanation of why that step is or isn't valid.