ktm5124
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 Apr 5 awarded Curious Apr 4 accepted How to solve a Pell equation using continued fractions Apr 4 comment How to solve a Pell equation using continued fractions I see. My program must be wrong. It only gets the correct convergents up until 393/109. Apr 4 comment How to solve a Pell equation using continued fractions You're right, my continued fractions are only right up until 393/109. Apr 4 revised How to solve a Pell equation using continued fractions [Edit removed during grace period]; added 64 characters in body Apr 4 revised How to solve a Pell equation using continued fractions deleted 1 character in body Apr 4 asked How to solve a Pell equation using continued fractions Mar 27 accepted First 10 digits of large sum Mar 27 comment First 10 digits of large sum I see. Is there any clever way to solve for the first 10 digits? I ended up solving it by writing my own BigInteger class (analogous to java.math.BigInteger). But I was looking for a clever solution! Mar 27 comment First 10 digits of large sum Haha, touche. So the carry from the last 38 digits could affect the outcome of the first 10? In fact... the carry from the last N digits could affect the outcome of the first 10, for any N >= 1? Mar 27 comment First 10 digits of large sum Thanks. I edited my post to say the first 12 digits. Mar 27 revised First 10 digits of large sum edited body Mar 27 awarded Commentator Mar 27 comment First 10 digits of large sum But your example only has 15 numbers. Is it significant that there are 100 in the Project Euler problem? (As multiplying any number by 100 shifts its digits two places over.) Mar 27 asked First 10 digits of large sum Jan 26 asked What can we say about the definite integral and Riemann sums? Jan 22 comment Prove log(xy) = log x + log y Right. I just don't see how $\int_{X}^{XY} \frac{dt}{t} = \int_{1}^{Y} \frac{du}{u}$ for your substitution of u. Jan 22 comment Prove log(xy) = log x + log y Oh, thanks for reminding me! The chain rule. I see what @columbus8myhw was saying now. Jan 22 awarded Critic Jan 22 comment Prove log(xy) = log x + log y It almost looks like you are factoring an x out of the integral, and I'm not well-versed enough with calculus to know why this is okay.