Calculus: A word that triggers involuntary fear spasms in the best of us. But the days of slogging through tedious textbook derivatives are over, if you want them to be. For the past few years, people ...

Back in 1948, the journal Physical Review published a paper entitled “Space-Time Approach to Quantum Electrodynamics” by a young physicist named R.P. Feynman at Cornell University. The paper described ...