And if you were chaining calculations (needed in all but the simplest problems), accuracy dropped with each successive operation. With slide rules, you had to keep track of the decimal point yourself: The slide rule might tell you the answer is 641, but you had to know if that was 64.1 or 0.641 or 641.0. Three digits was fine for real-world engineering, but not enough for finance. They were good to about three digits of accuracy, no more, in the hands of a skilled operator. Doing trig, like sines, cosines, and tangents? Easy. Slide rules are really good at few things. Mathematicians never carried slide rules, but astronauts did, as their backup computers.Įverything the slide rule could do, a so-called slide-rule calculator could do better-and more accurately.
![most expensive engineering calculator most expensive engineering calculator](https://miro.medium.com/max/679/0*c1IhluONKoSnegHd.jpg)
Rather, they are asked by working engineers, technicians, military ballistics officers, and financiers, all of whom need an actual number: Given this set of inputs, tell me the answer.īefore the modern era (say, the 1970s), these problems could be hard to solve, requiring a lot of pencils and paper, a book of tables, or a slide rule. Those sorts of questions aren’t asked by mathematicians, who are the people who derive equations to solve problems in a general way. At the current rate of rainfall, when will your local reservoir overflow its banks? If you shoot a rocket at an angle of 60 degrees into a headwind, how far will it fly with 40 pounds of propellant and a 5-pound payload? Assuming a 100-month loan for $75,000 at 5.11 percent, what will the payoff balance be after four years? If a lab culture is doubling every 14 hours, how many viruses will there be in a week?