Indeed, I have seen several announcements here, in Internet shops, similar to "Calls to foreign countries for 0.50 centavos a minute", when they clearly mean 0.50 Bolivianos, not cents.

>:)
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>http://verizonmath.blogspot.com/2006/12/verizon-doesnt-know-dollars-from-cents.html
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>>>http://www.runningahead.com/forums/topic/a4c5268206114ea39c33433c16c522ad
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>>Hmmm... I'll take up the challenge, and try to figure it out.
>>
>>The infinite sum is fairly easy, 1/2 + 1/4 + 1/8 + 1/16... clearly converges towards 1.
>>
>>For the exp(i * pi) part, I had to look up the definition of the exponential function, since I don't do complex math that often. From Wikipedia: exp(a+bi) = exp(a) * (cos b + i sin b), so here we have:
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>>exp(0 + pi * i)
>>= exp(0) * (cos pi + i sin pi)
>>= 1 * (-1 + i * 0)
>>= 1 * (-1)
>>= -1
>>
>>So it seems the entire check is for US$ 0.002 (0.2 cents) - assuming I didn't commit some mistake in the calculation.