½ñÈÕ³Ô¹Ï

Prime Exponent

As a budding physics major, I took Math 11 in 1955 as one of my first required courses. It was common knowledge that the ½ñÈÕ³Ô¹Ï math courses were not going to help us solve physics problems, so practical math also was taught. I never did well at math department offerings. I believe my supreme agony occurred under Prof. Joe Roberts’ patient nurturing the following year). Nevertheless, I did learn some useful rules along the way. Let me stylize 2 squared as 2^2 and 2 cubed as 2^3 = 2 x 2 x 2. The article “Prime Exponent” noted that Prof. Roberts retired after teaching 2^(2^3) - 2 years. However, 2^3 is 2 x 2 x 2 = 8, and 2^8 now becomes 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 256, so 2^8 - 2 = 254 years. I’d like to think that the purity of mathematics could lead to such longevity, but suspect that what you meant was (2^2)^3, or (2 squared) to the 3rd power = (4 x 4 x 4), or 64 – 2 = 62. With exponents you work backwards, or downwards, from the last one. Simple as this all seems, it is perhaps one of the few times I did anything correct with reference to math and ½ñÈÕ³Ô¹Ï.

—Roger Moment ’59
Longmont, Colorado

drop

Our postman brought the September 2014 ½ñÈÕ³Ô¹Ï magazine to our house on his motorcycle this morning. Skimming through, I noticed something rather odd in the article about Prof. Joe Roberts: he taught at ½ñÈÕ³Ô¹Ï for 254 years! Yes, that is the figure indicated in the subtitle, because 2 cubed = 8 and thus 2 to the 8th minus 2 = 256 - 2 = 254. Then again, perhaps we should be embarrassed, rather than amazed, that the writer, headline editor, and you all seemed to think 2 to the 2 to the 3 = 2 to the 6th or 64. This is what happens when our society at large disses basic calculation as mere “bean counting.”

—Martin Schell MAT ’77

Klaten, Central Java