Comment by xamuel

Before the discovery of the fundamental theorem of calculus, enormous ingenuity and whole careers were spent doing calculations which the fundamental theorem trivialized. To be clear, I'm not just saying that the people involved were doing lots of mechanical arithmetic (though they did that, too). I'm saying they did creative, inspired, nontrivial mathematics to calculate certain things, all of which was then trivialized and made obsolete by the fundamental theorem of calculus.