"And the trouble is / We don't know who we are instead."

## Thursday, March 10, 2005

### Even Google Gets It Wrong Sometimes

Despite the fact that "look it up on Google" has become the universal appeal to consumate earthly knowledge, even the nexus centered in Mountain View doesn't always get it right. Take this travesty, for example: according to Google's built-in calculator, anything divided by zero . . . equals zero! Of course this is completely wrong.

The expression x/0 is undefined for all numbers x. Not zero, but undefined. This is because division is defined as multiplying some number by the multiplicative inverse of another number. Thus, a/b is really a * (1/b). The multiplicative inverse of a number is the number m in the expression a*m = 1. Thus, the multiplicative inverse of 5 is 1/5, since 5 * 1/5 = 1. Thus, you may divide by 5, because 1/5 satisfies the definition of the multiplicative inverse of 5. Since no number m exists such that 0*m = 1, you cannot divide by zero.

I learned that in the first week of a class I eventually dropped. :-D

I wrote Google an email telling them of this horrendous error (shocking, really!), but still no response. The message of my email was essentially: "Bad Google! 5/0 is not 0!" The irony is that someone actually thought to hardcode the answer--in other words, actually running the divide by zero operation in a 'real' program would typically cause a fatal error. But this calculator program actually catches the divide by zero error and returns . . . zero?! Again, shocking.

My only hope is that by blogging about this (and getting millions of others to do the same thing), we can overturn this significant threat to the world's intelligence (how many young Googlers are being deceived every moment?!).

Join me!