Product Review: Casio FX115ESPLUS Scientific Calculator

 

I purchased this when I was taking chemistry because my teacher had a "no graphing calculator" policy for exams. I will say up front there are a lot of features I never ended up using because I had other graphing calculators, but not only does it have all the functionality of any scientific calculator (with the trig functions, etc.) it will also allow you to do derivatives and integrals, can solve a system of equations, store variables, etc. It is basically akin to a TI-84 without the graphing and programming capability. It is a great calculator, especially if you are in a situation where you cannot or do not need to use a graphing calculator.

Product Review: TI NSpire

 

I have almost all the TI line of graphing calculators including the 84, 85, and 89. The Nspire is very much overkill unless you are going into a hard science or engineering program, where you need to take higher-level math classes and use the concepts from those classes in future classes. In that case, it is very helpful and has a lot of advantages over the TI-89 once you get used to it.

One of the main advantages is that it is far better than the TI89 when doing integration. On the 89, you basically had to code in the integral in a format like int(x, x, 0, 10) to get it to do the integral. When doing integration on this,it is much like how you do it on the 84 plus where it gives you the integral setup like you see it in the book, you enter the limits of integration above and below the integral sign, then enter the function and then tell it what you are integrating over. And of course, unlike the 84-Plus it will give you the exact answer and not just a decimal approximation. The same is true with derivatives.

Where it really beats the 89 though is when doing integration and if you need to plug in a variable as your limit of integration, where the 89 would throw an error, this will actually do it for you. And you can even use the variable in your function as one of the limits of integration. For example, if you are an EE major taking electric and magnetic fields, when you get to Gauss's Law you often have to integrate over a variable like r, but also have to use r as one of the limits of integration. The 89 cannot pull that off, this one can. Also, the graphs it can produce are much better than the 89, especially 3D graphs which are light years beyond the crappy 89 ones.

The main thing I do not like about it is the battery. While it does have good battery life, and you can get a lot out of a charge, it is not something you can replace on your own. Unlike the 83, 84, 85, and 89 you cannot just pop the back off and put 4 AAA batteries in it. So you have to make sure it is charged well enough before you need to use it. The other thing I do not like, is I have yet to figure out how to get changing the mode from radians to degrees to stick. I can find it in the menu and change the option but then when I go back into a document or even open a new document it always stays in radian mode. Granted it is not a huge deal to just convert radians to degrees, but it is still a pain when it was much easier on the old calculators to do it.

The test mode issue is not something I have run into, but I had ample warning about it. Basically, if you end up in one of the main menus of the calculator there is an option that says "Press to Test" which gives no warning on what it does. You could realistically assume it means to run a diagnostic on the calculator, but in reality, it turns off much of the CAS capability and gets rid of some of the functions (like if you go into the trig menu you only get sin, cos and tangent and the inverses of those not the others). If you know someone that has the calculator you can connect them and get out of it easily, but if you do not, it is a total pain in the ass to get out of it. So basically, NEVER push that unless you are required to for an exam (in which case I would just use an 84-plus (or equivalent calculator) and don't bother putting this into the test mode).

I have not used every feature on the calculator and never will. But I have found it very good for what I have needed to do. I am not sure how it compares up against the HP 50 or some of the other comparable calculators by other manufacturers that are out there. It can be kind of humorous to read all the debates or arguments that go on about what is the better calculator, and my guess is they all have their strengths and weaknesses. So far I have been mostly satisfied with this and what it can do.

Product Review: TI-89 Titanium Graphing Calculator

 

This is probably one of the most powerful calculators out there, and as such you may or may not be able to use it in your classes (at least on quizzes and exams). If you are just taking algebra then this may be overkill for you because the real powerful features come when you get into calculus. It has algebraic symbolic capabilities, meaning it can solve equations and take derivatives and do most integrals for you, and give an exact answer not just a numeric approximation. It will not show you the steps, but it will give you the answers. Some teachers will not let students use it, even though just writing down the answer without showing any work will rarely (if ever) get you any points. One thing it is definitely good for even if you cannot use it on exams is for checking your work (especially when you are working on even number problems from the book).

There are a couple drawbacks to the calculator though. Sometimes, with very complicated derivatives and integrals the format of the answer will be given differently than what your book may simplify it to, and it is not always easy to see that it is a comparable result. This can be especially problematic when you have to do online homework and the program is picky about how the answer is entered. Second, if you are taking multivariable calculus, while this can graph three-dimensional functions, it gives you a very basic wireframe graph, that is hard to see the shape much less do any kind of analysis of it. Also, there are some functions that you can only access going into the catalog, and are not contained in the math, algebra, or calculus menus, so they can take a while to find. Most of the higher-level operations that you will use this for are however found in one of those menus.

If you are taking linear algebra and/or differential equations it is great. Once you learn how to enter the rows and columns of the matrices, you can do it very quickly off the home screen and row reduce or calculate the determinant in seconds. It can also solve first and second-order differential equations, which helped me immensely on my diff eq final, because I had one problem that I could not figure out initially, but I could see what the answer was, and as a result finally figured out how to get to it doing integration by substitution.

Overall, I think this is a great investment. It is not perfect, but for the price, it will help you, especially if you are in a program where you have to take advanced math classes.

Product Review: Texas Instruments Nspire CX CAS Graphing Calculator

 

basically give you exact answers to almost any kind of mathematical function. Of course, it does not show the work, so if you are taking a class, you still have to learn how to do the problems, but it is helpful for checking your work. The display is much, much better than the display on the TI-89. It does utilize the same kind of "stack" but it is much brighter and easier to see. And some things, like derivatives, integrals, and matrices are much easier to set up on the Nspire than they are on the TI-89. Another good feature is that you can have multiple windows open and go back and forth between them. Probably not something you would need for an exam (assuming your teacher allows you to use it), but it can be helpful when doing homework. Many teachers will not let you because this can also store PDF files (if you use the computer software that comes with it) so you could take a cheat sheet into an exam that is closed book, closed notes.

There are a few issues that I discovered along the way. The menus can be a pain in the butt to navigate unless you are using one of the common math functions. For example, the statistics material is hard to find and access. Second, you pretty much have to go to YouTube to figure out how to do things on it because it does not come with a manual that helps at all. And, doing some things like changing from Radian to Degree mode that is relatively easy on TI's other calculators like the 84 plus, and the 89, is tricky on the Nspire. Also, there is a very deceptive mode that is on one of the settings screens that says something like "press to test". At first glance, it looks like it would run some kind of diagnostic on the calculator, but what it really does is put the calculator into test mode which turns off most of the CAS functions, and getting the calculator out of test mode is very complicated, so much so that it is not worth ever activating. Basically, you need access to a second calculator that is not in test mode to connect to and go through a bunch of steps with the calculators connected to each other. So, if your teacher allows you to use the calculator on exams, but only if it is in the test mode, you are far better off using a non-CAS calculator. Also, on some of the derivative and integral solutions, it gives answers that are simplified differently than "normal" so it can be hard to check your answers. That said, one thing it can really do well is triple integrals in which you are integrating over dr, but also have r as a limit of integration. This is something that is done quite a bit in an Electric and Magnetic fields class (if you are an electrical engineering major). The TI-89 will throw an error, but the Nspire can actually calculate it.

Overall, I would say that if you are just taking lower-level math classes, then this is overkill. If however, you are going into an engineering program this will make your life much easier once you learn how to use the functions you need quickly. I cannot really say how it stacks up against any of the other CAS calculators (aside from the TI-89) out there. I know that some people love TI and some people hate TI, to the extent of breaking out in hilariously dumb arguments. But, I can tell you that you will probably not ever use every single operation the calculator is capable of, but if you are in an engineering program, it will help.