Sharp EL-W506T vs. Sharp EL-W516T

[Mjim]

(11-16-2019 06:14 AM)lrdheat Wrote:  The TI 30X Pro MathPrint is much faster than the 36X Pro, rather identical to the 991EX in speed and integration answers...I’m guessing that the TI is using the same integration method as the CASIO. Both the CASIO and TI correctly throw errors with the integral that you asked about. The 30X can accept much longer equations than the 36X Pro. I did not have the patience to test how lengthy an expression is possible, but much better than the frustratingly small capacity of the 36X Pro. I really like the 30X. I like how it uses a default epsilon of 1E-5 in it’s integration and differentiation operations, but in the math menu, allows the user to choose a much finer epsilon if desired...I can key in 1E-9, for example, or anything else that I might desire.

Never saw the TI-30X Pro MathPrint until today. Very much like the design and display...but it doesn't seem to exist outside of Germany, and what is available on ebay is expensive. In fact, I couldn't find a single review on it. It's a very nice looking TI calculator, but I wouldn't even believe it existed if not for the emulator and PDF manual I downloaded for it.

Looks like it has a pretty decent sized solar cell. I did a pretty rough test using my cellphone sensor, but the Sharp EL-W516X needed about 350 lux to work properly with indoor lighting or about 250 lux with overcast sky lighting (The measurement I did was pretty rough, so the difference may not mean anything). Would love to see more solar powered calculator reviews cover how well they do under different light situations.

TI-30X Pro MathPrint emulator impressions:
I'm not used to Texas Instruments calculators, so at first glance I'm not sure if I like the button layout; for example I like having a dedicated x^-1 key. On the other hand I do like how they did the inverse trig functions; a double tap to switch between both, nice design, much better than having them require the shift key. It's also great that there is a dedicated button for x (although on the sharp it's fairly easy compared to the Casio as well, since you can just double tap RCL to pick x).

Integration seems to work accurately like Casio. I got the same answer as the Casio by plugging in that energy equation a few posts above, and it wasn't too slow (fx-9750GII is much faster, but that isn't unusual comparing a solar powered scientific calculator vs a graphing one). Nice to know I can trust the integration on this.

Differentiation seems slightly better than the Sharp EL-W516X; but isn't as good as the Casio fx-991ex and suffers by losing digits (like the Sharp) when you specify smaller epsilons:

d/dx(e^(x^3),x,x=6):

Casio fx-991EX:
6.934766564*10^95 (default epsilon, but accurate for all displayed digits)

Sharp EL-W516X:
6.93477882*10^95 (default epsilon)
6.93568*10^95 (epsilon = 1*10^-10)

TI-30X Pro MathPrint:
6.934767925*10^95 (default epsilon)
6.93475*10^95 (epsilon = 1*10^-10)

It's kind of annoying that it loses digits by specifying a smaller epsilon, but I guess the TI-30X Pro MathPrint still holds it accuracy better than the Sharp.

Numerical solver isn't quite as nice as the Casio, for example:

e^2x - 3 = ln(2x + 1)

You can see there will be a problem when x = -0.5 for the log on the right. Both the TI & Sharp will throw up error messages when using x=-0.5 (though the TI will at least let you know it was a bad guess rather than Sharp's non informative ERROR 02). The Casio fx-991ex somehow figures out a way to work around the bad guess and will solve the problem anyway. The solutions returned are pretty accurate for all 3 calculators (mostly differences in the hidden digits), but Sharp is the least flexible only solving for x and requiring everything to be on the left side.

Table function is good and seems to work the same as the new Sharp EL-W506T; you specify a starting point and interval, but can scroll forever in either direction.

Calculation History seems comparable to the Sharp as well, but showing the results of previous equations on the same screen is so much more useful (Seems silly that Sharp wastes all that screen space by only ever showing the current problem you are working on and not the previous calculation history).

Tried typing in that formula in the Expression mode, but I couldn't fit the last 1/3rd of the equation in. The TI-30X emulator didn't actually bring up a buffer full message, just kind of stopped me typing any more of the equation.

That "set op" function seems to work the same as the equation storage on the Sharp; so I guess between that gives effectively 5 equation memories (set op, num-solv, expr-eval, and the 2xTable functions (f(x) & g(x)) ), although I'm not sure (except from "set op") if you can copy them to the main display.

That Data editor looks pretty good as well, though I got stuck when trying to enter an equation in on of the columns (wanted to see if I could save more equations there!); the sequence operation worked a charm though.

I did try to integrate sin(x)/x on the interval [0, pi/2] and you are quite right about handling undefined intervals as when x=0. The TI-30X Pro mathprint can deal with the division by zero no problems and can even handle a wider interval such as [-pi/4, pi/2], where the division by zero isn't at the end points. I was surprised that the Casio fx-991ex couldn't deal with this, despite using a better integration algorithm than the Sharp (the sharp did indeed fail as well with this).