## Girls’ Angle Bulletin, Volume 5, Number 5

Counting problems seem to keep popping up at Girls’ Angle lately.  That’s why we included Shravas Rao’s introduction to permutations and combinations in the last issue of the Bulletin, and that’s why you’ll find a 2 page Summer Fun problem set by Shravas in our latest issue.

But let’s start with the cover, which showcases every way of coloring a certain T-shirt with 3 colors from a palette of 5.  Which T-shirt do you like best?

Jean Pedersen

Open the cover and find the second part of our 3-part interview with Santa Clara professor of mathematics Jean Pedersen.

Amelia Earhart

On July 3, 2012, The International Group for Historic Aircraft Recovery (TIGHAR), is lifting anchor in Honolulu bound for Nikumaroro, a small island in the South Pacific. Years of research led them to suspect that famed aviator Amelia Earhart and her navigator Fred Noonan crash landed and lived on Nikumaroro as castaways. In Math In Your World, learn about triangulation, a mathematical technique that played an important role in their investigation.

Mysterious Zeroes

Then explore a mystery in Anna’s Math Journal.  Anna has been investigating sums of perfect kth powers for a number of issues now.  Last time she was led to defining a sequence of numbers that relate to the coefficients of these polynomials.  She derived a recursion formula for the sequence and computed the first 9 values.  Strangely enough, every other term came out to be zero.  Is that a general pattern? If so, why?

What’s log a + log b?

Stamp out and a very common error handling logarithms in Errorbusters!

Dividing by m/n is equivalent to multiplying by n/m

If you’ve ever wanted to understand why, it’s all in Coach Barb’s Corner.

Summer Fun

Have you ever wondered how much time professional tennis player’s have to react when they are trying to return Serena Williams’ serve at Wimbledon? Or why it isn’t uncommon to see club players smashing balls right into the net? Would you like to become a master of the absolute value function? Does the symmetry of regular polygons appeal to you?

All these questions are addressed, and more, in this year’s batch of Summer Fun problem sets.  The best way to learn math is to do math, and these problem sets are an opportunity to get active.

We hope you enjoy our latest issue… it’s free at our website.  Well, almost all free.  We’ve truncated the interview with Prof. Pedersen as an enticement to subscribe. Thanks to our sponsors, we are now able to offer annual subscriptions for \$36/year.  Consider subscribing for yourself or as a gift for someone or for some organization such as a middle school or high school.  It all helps support our nonprofit mission.