If I enter the expression

35+42√2

into my graphing calculator and then ask it for the fractional (rational) equivalent it cannot do so. Since the number is irrational it displays the first few decimal digits:

94.39696962

However, if I enter the expression

55+42√2

into the same graphing calculator and then ask it for the fractional equivalent it displays:

37751
-----
 330 

But this second number I entered is clearly not rational either.

What's going on?

(In reply to re: solution by Jer)

It's all the more surprising since I thought big-name calculator companies like TI  and HP carried guard digits up to 12 or 13 significant digits, even while displaying only 10.

Posted by Charlie on 2015-05-31 14:09:48