Maths, clearly

# Errata: The Maths Behind

p11: The figure for flying in the green circle should be 1000 miles. (12,000 miles refers to the risk specifically from terrorism.)

p19: 50 names, rather than 40, would have died out.

p26: Israel’s nuclear arsenal is believed to be around 80, rather than 80-20.

p29: where I have “(but not the obligation) to buy”, I should have “… to sell”. Further, in both inequalities, x should be P.

p30: The first = in the Black-Scholes equation should be a +.

p43: hexagons in fact have the smallest perimeter-to-area ratio.

p55: I have “ten-thousandth of a newton”; it should be “hundred-thousandth”.

p68: 65 is in fact, 1 000 001 in binary, and 101 is 1 100 101.

p71: There is an error in the formula. It should read “Total people up to level $n$: $\frac{6\left(6^n – 5\right)}{5}$. Similarly, the last formula should read $k^n -1$ rather than $k^{n-1}$. The blue circle should say “13” rather than 12.

p74: I have miscounted and miscalculated here. I think a G has disappeared from the analysis and several knock-on errors have occurred. Gracias to my Spanish translator for spotting this!

p83: Start and End should be switched.

p97: “better” should not be in the green circle.

p115: you can’t solve (6/7)^N. You can solve $\left(\frac{6}{7}\right)^N = 0.5$, which is what I meant.

p117: Typo – for Bond Sreet, read Bond Street.

p129: Typo – “if Mother” should have a capital I.

p133: The graphs here are a mess, and I’m not sure what I was trying to get across with them.

p150: The bottom line of the figure should read “Accelerates to 3”

p151: The 45-minute roads are A to Y and B to X.

p158: The wing pictured is not practical for flying. The underside should be less curved than the top.

p166: We’ve typeset $\sqrt{\frac{n}{2}}$ rather than $\frac{\sqrt{n}}{2}$.

p169: The picture does not match the description. Hopefully you can mentally rename the shapes as appropriate.

p170: 3 in 56 is about 1 in 19, not 1 in 17. I am not certain why the graph shows statistics for a 45-ball lottery, something the UK has never had.

p177: There is a 99.7% chance of a mismatch, not of a match; the labels in the figure are reversed.

p181: A ‘ln’ has gone missing; it would in fact score $\ln\left(\frac{0.8}{0.2}\right)$.

p184: Embarrassingly, I referred to the winter solstice as an equinox. Good grief.

p185: There is an error in the diagram; the lower arrow does not belong and the caption should read “extra evening daylight”.

# Errata: Cracking Mathematics

On p127, I say Mersenne overlooked $M_{69}$, $M_{89}$ and $M_{127}$; he actually overlooked $M_{61}$, $M_{89}$ and $M_{107}$. Thanks to Maisie Shepherd for spotting my error!

On p165, the infinite  sum should read $\frac{1}{0!} + \frac{1}{1!} + \frac{1}{2!} + \frac{1}{3!} + \dots = 1 + 1 + \frac{1}{2} + \frac{1}{6} +\dots$. Thanks to Peter Skelton  who  alerted me to  this.

On p274, I refer to “Isaac” Halperin. Professor Halperin’s forename was, in fact, Israel. Thanks to Alain Duncan for pointing this out.

# The Maths Behind…

“Even knowledgeable mathematicians will learn something, and those who teach mathematics will find it invaluable in answering the question ‘when would you ever use maths in everyday life?’”

“The book manages to walk the line between being readable and demonstrating how [the maths] works very well”

• How does the rollercoaster stay on the track while upside-down?
• How does DNA testing work?
• … and how do penguins stay warm?

The Maths Behind… takes a look at the mathematics behind the everyday, from sports to politics, from computers to shopping.

> See the errata page.

> Buy The Maths Behind… at Amazon

# Cracking Mathematics

• How did logarithms come about?
• Is Alice In Wonderland really about mathematics?
• And why was a Swedish mathematician presented with a goose live on national TV?

Cracking Mathematics, an unreliable history of maths, answers all of these questions (and plenty more besides) – from the birth of counting to the heroes of modern mathematics.

> See the errata page

> Buy Cracking Mathematics at Amazon