Many sailors use calculations for boat ratios, perhaps rigging
, or navigation
So, this should be easy right?
Here's a mathematical proof that appears to show that 2=1. Can you find what's wrong with it.
Then x^2=xy (by multiplying both sides by x)
Then x^2-y^2=xy-y^2 (by subtracting y^2 from both sides)
Then (x+y)(x-y)=y(x-y) (by factoring both sides)
Then x+y=y (by dividing both sides by (x-y))
Then y+y=y (since x=y by the original assumption)
Therefore 2=1 (by dividing both sides by y)
Clearly 2 and 1 are not equal, what mistake was made above?