In this video, I explain how to use Pythagorean identities to simplify trigonometric expressions. We focus on substituting ...

The camera roll of an outdoor lover is guaranteed to contain several images of them standing next to a trig point marking the summit of fells, moorlands and crags. Now a charity wants the ...

We spend a lot of time thinking about the difficult people in our lives—the friend who can't take feedback, the partner who always has to be right, the coworker who turns everything into a fight. But ...

Pillars at Cold Ashby, Northamptonshire, and Thorny Gale, Cumbria, bookended the project that modernised mapping Heritage campaigners are bidding for listing status for two concrete pillars hailed as ...

👉 Learn how to verify trigonometric identities involving the addition and subtraction of terms. To do this it is usually useful to convert the addition or subtraction terms in terms of one ...

One idle evening last October, Mehtaab Sawhney took up an old pastime. He began perusing the website erdosproblems.com, an updated record of the 1,179 conjectures left behind by the eccentric and ...

What are the most pressing global crises in 2026? Each year, the International Rescue Committee’s (IRC) Emergency Watchlist identifies the countries at greatest risk of new or worsening humanitarian ...

This is an updated version of a story first published on May 5, 2024. For many high school students returning to class, it may seem like geometry and trigonometry were created by the Greeks as a form ...

Sven, a sales leader, received a call from a major customer who was furious. Their order arrived late, the product was damaged, and to top it off, their invoice didn’t reflect the volume discount ...

Consider someone who’s perfectly content with their office chair. It’s not ergonomic, it doesn’t have lumbar support, but it works. Then, during a meeting or a visit to a friend’s office, they sit in ...