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Lent my 33s to a guy to prepare for the fall FE test. Despite this guy's long HP48 use, he did not like/could not get used to the 33s. He returned my 33s and went out and bought a Casio 115 for just $14.95 at Walmart.

I played with his Casio for a while. I liked the looks of of the machine, a sleek silver design. Considering the ugliness of the 33s cowcatcher design, the Casio looks better. Using it was very easy and intuitive, algebraic entry, while not my favorite, has the beauty of being able to enter in very long expressions with no error. The features included exact fractions, numeric differentiation and integration, matrices, complex numbers and a solver. All of these worked without a hitch.

In short, I was suprised at all the features included in a machine just $15 in cost. To anyone out there needing a calculator to take that abomination of an FE test, and not wanting to spend hundred$ on an HP32 or even $60 on an HP33, I would heartily recommend the Casio.

All of this begs the question that others have asked here off and on: where is HP's great little rocksolid, bulletproof, works like a champ, cheap, (say < $25) RPN scientific? Only in our dreams, I fear...

Considering that Hp used to sell the Hp20s for about $30, why can't they sell a great $30 RPN. The Hp20s was an excellent quality calculator with the preferred (by us RPN bigots) keyboard and layout. Could have included an RPN mode and would have made this a great must have calculator. Sold well even though it was 2-3 times more than other algebraics. Only recently discontinued to sell the $15-20 Hp30s or $10-15 Hp9s. What progress!!!

During the HHC 2005 conference in San Jose, Richard Nelson made an interesting comment to the folks from HP's calculator division. Richard suggested that HP manufacturs an HP-45-like calculator and sell it for $20. HP can also give it away to teachers' conference to get folks' feet wet with RPN.

Namir

My brother who teaches math in college recommends the 115 for his students. He likes the thing quite a bit. His favorite calc is a 41CX blanknut I gave him years ago.

This is exactly why when I saw TI36X solar powered calcs for sale for about $7 each, I bought a half dozen of the things. By buying that many, I actually got a better price. I also bought some HP10BII's at about $8 each.

I am a die-hard RPN fan, and for real calculating I prefer a 42S or a 48GX, but for less than $10 the TI36X is a great calculator. (It is about $18-20 at your local Walmart)

Besides, when it falls on the floor, I don't gasp and inspect it for damage. When one of our kids forget their calc (college), I just give them a new TI36X to use as a backup.

I prepared for and took the FE and PE with my 42S and 48GX calcs, but they are not necessary to pass the test. Mastery of your subject area, knowing your calc of choice inside and out, time management, and controlling your anxiety are the essential components of passing.

The current-model calculators that seem to get the most mention among EIT/PE candidates are the Casio 115 (full model name is the Casio FX-115MS Plus), the HP-9G, and the HP-33S. The 115 is the value choice for $15. The 9G is more expensive, at $30, but offers some programmability. The 33S is the most expensive, at $60; it offers nearly unlimited equation storage, the most programmability, and RPN.

A few limitations to the 115:

-- The 115 has no financial functions. These come up on the EIT exam, which includes engineering economics problems. The 33S can be easily programmed with the time value of money equation, and is therefore much faster for such problems. If I were using the 115 on an EIT exam, I might take a cheap financial calculator as well.

-- The 115 has an equation solver, but I believe that it only handles cubic and quadratic equations. It is not nearly as versatile as the solver in the 33S.

HP can sell inexpensive scientific calculators (6S, 9G, 9S, 20S, 30S). But for whatever reason, they cannot or will not sell inexpensive scientific calculators with RPN.

TI does not seem to be keeping pace in the non-graphing scientific market. For $15, you can get a Casio 115 that can do complex math, numeric integration and differentiation, solve cubic and quadratic equations, and solve simultaneous linear equations with 2 or 3 unknowns. It doesn't hurt to have these features for the EIT exam; they can save time if you know how to use them.

The TI-36 offers fewer features for (typically) about the same price, so it seems less attractive than the Casio.

indeed. ive often said that the hp20s is an underrated machine. its biggest drawback for hp fans is the lack of rpn, which is a mistake. otherwise, the machine itself is a great little scientific. just the sort of thing to use on the road. compared to the 32sii and the like, its light on functionality, but it benefits from a much cleaner layout and highly readable display. the well built pioneer style and slim design makes for excellent pocket size.

the rom program idea is quite neat. a great plus for a remake (as well as more memory), would be to be the ability to call up a whole library of programs. roms are cheap now.

>-- The 115 has an equation solver, but I believe that it
>only handles cubic and quadratic equations. It is not
>nearly as versatile as the solver in the 33S.

The quadratic and cubic solvers can give imaginary and real roots. But it also has a general solver that can find a real root to (virtually) any equation with something like Newton's method.

Actually, virtually *any* current 2-line algebraic calculator with an "ANS" memory key can fairly easily find roots. Just enter any number as a seed, hit equals, then type "ANS - f(ANS)/f'(ANS)", (with f and f' being the function you're zeroing and its derivative) and hit "=" over and over to iterate. (This could be used, for example, with the TI-30XII, which doesn't have a solver)

But the 115 does it better, since you don't need to find the derivative, and it iterates automatically, without need to hit "=" over and over.

BUT, the 115 has an overlooked feature that I have used to solve 2 variable equations with Newton's method!

It's based on the line copy feature. It's possible to copy several commands to one line, and then repeatedly step through all of them by hitting "=" over and over. The example the manual gives makes this seem like a completely useless feature, until you realize the lines can both make use of variables and update them.

It's not that great compared to calculators that can *really* program, and this method only works for simple cases (there's something like a 70 keystroke limit). But maybe some calculator junkies would be interested nevertheless.

As an example, I once tried to solve the complex equation Z = exp(Z), or (x + y i) = exp(x)(cos(y) + isin(y)), or

x - exp(x)cos(y) = 0 = a y - exp(x)sin(y) = 0 = b

So, Newton's method would involve

[da/dx da/dy] [-dx]


[db/dx db/dy] [-dy]


==

[a]


[b]

It turns out for this example, da/dx = db/dy, da/dy = -db/dx. To store da/dx, I used the variable "C", and for da/dy I used "D".

So, this is how you type in the problem.

2 -> X

2 -> Y [Arbitrary seeds]

X-eXcosY -> A

Y-eXsinY -> B

1-eXcosY-> C

eXsinY -> D

X + (BD - AC)/(C2 + D2 -> X

Y - (CB + DA)/ (C2 + D2 -> Y [Cramer's rule]

After this, you hit "up" enough times to take you to the first non-seed line ( X-eXcosY -> A ) and hit copy. Then hitting "=" over and over iterates. This sure beats typing in those formulas over and over for every step, and it converges pretty quickly, too.

You can also use this sort of trick with this calculator to, for example, making adding series easier.

I have a fx-115MS (not "Plus") that I bought about a year ago. I was intrigued by its complex-number functions for a mere $15 price. I wanted to see "modern thinking" in calc design, and see how good the complex-number capability was.

Summary: Very impressive set of features, speedy, and a crisp, highly-legible LCD display. Lotta stuff for the price. However, it is not a well-engineered, cohesive tool; it is more of a "learning aid" for pre-collegiate students.

J.C. Randerson posted about the "Casio 115":

Quote:
Using it was very easy and intuitive,

Can't say that I agree with that:

  • The keyboard is a bit cluttered; a few things are unintuitive.
  • The so-called "Super Visually Perfect Algebraic Method" (S-V.P.A.M.) offers little consistency for entering operations in expressions -- sometimes prefix, sometimes postfix, sometimes infix...
  • Simple tasks are buried in deep "mode menus". How does one speciffy 5 decimal places via "fix"? [mode][mode][mode][mode][mode][1][5]. Yeesh!

Quote:
The features included exact fractions, numeric differentiation and integration, matrices, complex numbers and a solver. All of these worked without a hitch.

Yep, it's got all that -- although "matrices" is limited to solution of real exactly-determined linear systems of order 2 or 3; and the "complex numbers" function set is limited to basic arithmetic and integer-valued exponents.

But, here's the problem: These functions are executed though different "modes", which don't work together cohesively as on, for example, the HP-15C. The fx-115 user enters "CMPLX" mode to perform complex-number calculations, which makes other features temporarily unavailable. The fx-115 user enters "EQN" mode to solve a linear system or polynomial of order 2 or 3, then loses all the entered coefficients when a different mode is selected.

As long as the user does only one thing at a time (whatever the "lesson of the day" is), I guess that's OK.

Quote:
In short, I was suprised at all the features included in a machine just $15 in cost.

Me too, but if I wanted a straightforward NCEES-approved calc for the PE exam, I'd go with my HP-32SII or TI-36X. The 33S could be a repository of equations, including TVM.

I'd also prefer the discontinued HP-11C, HP-15C, or HP-20S over the Casio. All of these meet their standards, and I have lobbied NCEES to add them to their list.

Edited: 26 Oct 2004, 9:34 p.m.

What? No programs? Forget it!

[VPN]

Quote: "For $15, you can get a Casio 115 that can do complex math, numeric integration and differentiation, solve cubic and quadratic equations, and solve simultaneous linear equations with 2 or 3 unknowns. It doesn't hurt to have these features for the EIT exam; they can save time if you know how to use them.

The TI-36 offers fewer features for (typically) about the same price, so it seems less attractive than the Casio."

You are right, for $15, it sounds hard to beat. However, I do all of simultaneous equations, quadratics, and calculus by hand anyway, testing or at work. I don't want to make a keying mistake. Besides, I was faster that way. The FE/PE exams are all about time management. I saw several folks growling and smacking their calc during these exams. Just having a powerful calculator will not allow folks to pass these tests.

Still, for a combined cost of about $14 I could take my TI36X and my HP10BII and have a great combination for these tests.