Here is the famous proof that tumbles the very foundations of mathematics:

Proof that 1 = -1.

-1  =  -1 Assert that -1 = -1.  1    =   -1  -1  1 Express -1 in two different, but equivalent ways.   =     1   -1   -1   1 Take the square root of both sides   =     1   -1    -1   1  Use the fact that    =     x    x    y    y   1    =    i   i  1 Simplify all the square roots.  Note that the square root of -1 is defined as i.   i     =    i²   i  1 Multiply both sides by i. 1   =    -1    1 i/i is 1, and i² is -1. 1  =  -1 Proof is complete!

Related pages in this website

Index of joke proofs

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