Mathlab Android App Review
Developer: Mathlab
Apps, LLC
Cost: Free
Version, and a Paid Version $4.99*
Engine: Android
* For some reason
apps through Google Play, sales tax is charged for downloaded apps.
Review
My focus will be on the paid version. The free version does not have 3D Graphing,
the ability to store constants, functions, or expressions.
The calculator app has three main modes: Calc, Graph, and Table.
Calc Mode
From the initial looks of things, the keyboard on the
Calc mode is simple with a limited amount of functions. Don’t let the minimalist look fool you. Behind many of the keys lie many additional
functions, which can be accessed by either repeated presses of the button or
holding down the button to access functions.
For example:
Holding the n! key grants access to n!, nCr, and nPr.
Holding the x^n key grants access to x^n, x’, x” (for
derivative calculations). Yes, Mathlab
does the symbolic first and second derivative of f(x). You can combine x’ and x’’ for third and
higher derivatives. With the degree key
(°), x’ and x’’ can be used to execute calculations using degrees-minutes-seconds.
Holding the √ key grants access to square roots, cube
roots, and quartic roots.
To switch between trigonometric and hyperbolic functions,
press and hold the π and e keys, respectively.
And yes, you get access to the csc, sec, and cot (and all the relative
functions) on both modes. The angle
modes available are Degree and Radian.
When you enter fractions, Mathlab displays answers in
both fraction (mixed and improper, if necessary) AND the decimal
equivalent. Displaying multiple forms is
also present in calculations involving degrees-minutes-seconds and
factoring/expanding polynomials.
Just enter the calculation and the app makes the calculation
for you, despite the presence of an equals key. Calculations are terminated by pressing the
return key. I have to admit that this
takes getting used to. Also, when
entering expressions, I found it is easier to look at the entry line above the
output screen rather due to the automatic calculation. Entries on the output screen are shown in
textbook style.
This doesn’t mean that the equals key is useless. Mathlab
also solves equations and inequalities.
Once a variable is solved for, the value is stored in the variable. If you want to execute a new calculation with
the same variables (x, y, t, z, r, θ), press and hold the clear [C] button or
start a new worksheet.
Calc also features matrices, vectors (the multiplication
key holds both the dot and cross product), and full complex number
support. However, the factorial function
only works with integers. (You definitely can go higher than 69!). For the matrix functions norm, tr
(transpose), and det (determinant), you’ll need to type them in manually.
Mathlab can also convert numbers between binary, decimal,
octal, and hexadecimal mode. Start binary, octal, and hexadecimal numbers with
0b, 0o, and 0x, respectively. Conversion
functions include bin, dec, oct, and hex.
Graph
Graphing allows you to graph functions, polar equations,
parametric equations, and 3D (Pro version only). You can trace on anything that is graphed by
holding down on the screen and tracing the graph with your finger. If applicable, extreme points and roots are
shown. With the Calc mode, just swipe
the keyboard down for more of the output screen, until you are ready to operate
again.
For polar equations, insert the variable θ. For parametric, two expressions will be entered. The first will be in the format x = f(t),
press Enter, then enter the second in the format y = g(t).
For 3D, entering equations to be graphed is simple as in
2D mode. Mathlab defaults to colorized
mesh graphs, but if you want, you can turn off color and/or change 3D graphs to
dots.
Graph also offers inequality graphing. Unfortunately there is no shading, you get arrows
that indicate which area of the graph is covered.
If you enter a vector with an even number of elements,
you can create a scatterplot. The vector
will be in the format [x1, y1, x2, y2, …, xn, yn]. You can tap the vector on the
left side of the screen below the input screen (check mark) to get a linear
regression line.
Again, Mathlab does an excellent job getting many
functions in the little space of the phone size.
I also like the ease that you can zoom and scroll graphs. The app is very responsive.
Table
The Table function is an extension of the Graph
mode. Enter your expression in Graph
mode and switch to the Table to see it.
You can also enter additional expressions outside of Graph mode. The zoom and scroll also work dynamically and
well.
Storing Constants and Functions (PRO Only)
You can use the alphabetic and Greek keyboards to define
constants and functions. Obviously, if
you plan on using the app for an extended period of time, it pays to get the
Pro version. You will need to type in
all your constants, since Mathlab doesn’t provide a pre-library of constants.
Help
There are two help pages.
The first comes with the app, and it is just a quick help page. You do get the full keyboard mapping on this
page. The second page is through Mathlab
website (help.mathlab.us for the United States site) and is very thorough.
Final Thoughts
I’m impressed on how Mathlab manages to organize many functions
into what looks like a minimalist (clean) keyboard. The automatic results are great and the
zoom/scroll dynamics of graphs and tables are awesome. You get a lot for the Free version, but if
you plan to use this app for a long period of time, I would recommend getting
the full version, particularly for the ability to store constants and
customized functions.
This blog is property of Edward Shore. 2015.
