While talking about Leibniz, who isn’t the inventor of calculus — but is the person I’d credit most with showing us how calculus could be — I made some speculations unsupported by evidence about whether he looked into optimization problems. This because of the philosophical work that he’s famous for among lay audiences, the proposition that God’s will implies this must be the best possible universe. (I don’t know what he’s most famous for among professional philosophers.)
I don’t have an essay specifically on optimization theory, as mathematicians see it. Not exactly. But last year I did write about linear programming, which is a particular type of optimization problem. It’s a kind that’s often the best we can do in a complex circumstance. And it lets me introduce you to the word “simplex”, which is fun to say.