CasioNew FX-991CW Advanced Scientific Calculator (UK Version)

Buen equipo. Excelente rendimiento, muchas funciones.

Easy to figure out how to use it. Visible keys and interface

Espectacular

The four calculators are:1. The TI-36X Pro (scientific calculator)2. The Casio fx-115ES Plus (scientific calculator)3. The Casio fx-991EX ClassWiz (scientific calculator)4. The Casio fx-9750gii (graphing calculator)The problem used for test:B = 1.3271244e+20C = 6.957e+08D = 1.495978707e+11Evaluate:∫ (C, 0.999999D) 1 / √(2B(1/x − 1/D)) dxThis integral returns the amount of time, in seconds, for an object to fall to the sun's photosphere (one solar radius = C) starting from a distance of 1 astronomical unit (D), assuming that the sun and the object are initially at rest with respect to each other and are acted upon by no forces other than their mutual gravitational attraction. The variable B is the solar gravitational parameter.TI-36X ProAnswer: 5570898.581Time to Solve: 90.4 secCasio fx-115ES PlusAnswer: 5570898.583Time to Solve: 76.6 secCasio fx-991EX ClassWiz ← this calculator is being reviewedAnswer: 5570898.583Time to Solve: 17.3 secCasio fx-9750giiAnswer: 5570898.583Time to Solve: 4.9 secAs you can see, the Texas Instruments device is a slow-poke. The TI-36X Pro costs anywhere from $19 to $30 on Amazon.The Casio fx-991EX ClassWiz is the official (and substantial) Casio upgrade to the earlier Casio fx-115ES Plus. For moderately complicated numerical integration chores, the Casio fx-991EX is more than four times faster than its predecessor model. Furthermore, the Casio fx-991EX is more than five times faster than its ostensible competitor from Texas Instruments, the TI-36X Pro. The Casio fx-991EX sells at prices ranging from $14 to $36 on Amazon.But the Casio fx-9750gii is more than three times faster than the Casio fx-991EX ClassWiz and is about 18 times faster than the TI-36X Pro. Reasonable prices on Amazon go from $30 to $37, but there are some sellers (that should be ignored) who are trying to gouge for more.I have solved the indefinite integral analytically. Omitting the intermediate steps,∫ 1 / √(2B(1/x − 1/D)) dx= √[D/(2B)] { √(XD−X²) + D arctan[√(D/X−1)] }When I used the calculators to solve the integral numerically, I had to avoid entering D itself for x, since that would cause an overflow error. But in the analytical solution, when X=C, the answer is 5578001.670517. When X=0.999999D, the answer is 7103.088517. So the precise answer from the analytical solution, used twice to evaluate the integral from X=C to X=0.999999D, is 5570898.582. There is no appreciable error in the numerical results from any of the calculators.

Nice .. I like the look and the weigh

Es una calculadora que cumple con su función.Me ha sido muy útil en mi carrera de ingeniería.

The installation of the RAM is easy, as long as you have the right direction, you can just simply just push down until you hear the slot lock click sound. Computer system recognizes the memory smoothly. No complaints so far…

Got this for one of the kids GCSEs, it's great, cheaper than the shops for the same item. Has all cool features and will definitely help the kid with her calculator papers, she has trouble with unit conversion but there's a catalogue on tge calculator for that too. Worth every penny.

This calculator has been my trustworthy companion for school and homework. This calculator is a powerful tool, allowing me to breeze through complex mathematical equations and scientific calculations effortlessly. If you're a student in need of a reliable calculator, I highly recommend this one. It's a compact and relatively affordable choice that won't disappoint.

Super gerat

Sympathique machine, parfaite pour l'informaticien grâce aux conversions entre bases (binaire, hexa, decimal).Intègre la résolution de fonction, les intégrales et la factorisation (de petit nombre).Seul regret, pas d'historique permanent.Quand on l'éteint, tout est perdu.