## Girls’ Angle Bulletin, Volume 12, Number 4

We open with the fourth and final part of our interview with mathematician Dr. Kristin Lauter, a professor at the University of Washington and a principal researcher at Microsoft Research. In this segment, Dr. Lauter addresses gender issues in mathematics and gives advice to students. We hope you enjoyed this 4-part interview with Dr. Lauter.  We certainly did! A huge Thank You to Dr. Lauter and to Ke Huang for conducting the interview, which took place in April, 2018 at the University of Washington.

Next up is another wonderful installment of The Needell in the Haystack by Deanna Needell, this one on P vs. NP, the traveling salesperson problem, and Hamiltonian paths.

Emily and Jasmine continue their mathematical adventures getting deeper into their exploration of zigzags across rectangles. They’re making steady progress, increasing their knowledge of the patterns produced.

Then we have a peculiar problem set designed to induce you to think more conceptually about mathematics. Each of the problems in our “Anti-Calculator” game can be solved with a minimum of computation. In fact, you might find that you can solve them all entirely in your head and would encourage you to try.

We have an installment of Learn by Doing on the standard form of a line. If you’re a veteran of lines, most of this will be familiar, but perhaps the last two problems will not. If you’d like to try the last problem without seeing the result (which is in the problem statement), find a formula for the area of a triangle bounded by the lines $A_1x+B_1y=C_1$, $A_2x+B_2y=C_2$, and $A_3x+B_3y=C_3$, assuming that no two of these lines are parallel.

We then show how to see that the area under $1/x$ gives the logarithm without using calculus.

We cover the floor and ceiling in Notation Station, and close with a few Notes from the Club.

We hope you enjoy it!

Finally, a reminder: when you subscribe to the Girls’ Angle Bulletin, you’re not just getting a subscription to a magazine. You are also gaining access to the Girls’ Angle mentors.  We urge all subscribers and members to write us with your math questions or anything else in the Bulletin or having to do with mathematics in general. We will respond. We want you to get active and do mathematics. Parts of the Bulletin are written to induce you to wonder and respond with more questions. Don’t let those questions fade away and become forgotten. Send them to us!

We continue to encourage people to subscribe to our print version, so we have removed some content from the electronic version.  Subscriptions are a great way to support Girls’ Angle while getting something concrete back in return.  We hope you subscribe!