## Sunday, October 28, 2012

### Review of FreeCalcFxc

Review: FreeCalcFxC

Platforms: iPhone and iPod Touch, will run on an iPad

Versions Available:
Free Version
\$0.99 Scientific Version
\$0.99 Financial Version

The only difference between the Free Version and the Scientific Version is that the Free Version is ad-supported.

Keyboard

The keyboard is a simple layout of 34 keys. The keys are labeled with one function. To access the shift function, press the gold shift key. The names of the shifted function replace the primary functions. Kudos for simplicity, however, my personal preference is to see both the primary and shift functions at the same time.

RPN and Algebraic Mode

The default mode is RPN (Reverse Polish Notation), but you can always enter an algebraic formula by pressing the "=f" key. The "=f" becomes the "=" to terminate entry of the formula.

Many, many, many calculators are available

Accessing the Focused Calculator list gives many calculators such as Math and Trig (the main calculator), Time Value of Money, Bonds, Statistics, Probability and Conversion calculators. For me the Conversion calculators leave a little to be desired, since there are no direct conversion keys attached to the default keyboard (luckily, that can be remedied!).

In addition to the Focused Calculators, CalcFxC gives formula template calculates. Among these formula calculators you have Percent Change, Distribution Functions, and the Quadratic and Cubic Equations.

The keyboard gives a good response when the "keys" are pressed. The screen is a two line (adjustable) screen which displays the y-stack and x-stack. The stack is four levels.

Help can be accessed by pressing and holding a key.

Real Numbers and Limits

The calculator operates on real numbers only. So, entering √-1 will return an error. As a consequence, the polynomial solvers return only real roots. The numbers range in the order of -10^-308 to 10^308.

There are no fractions or exact values of trig functions.

Math and Trig Keyboard

sqrtpi: takes the square root of the number then multiplies it by π
exmp1: e^x - 1, known on Hewlett Packard Calculators as the EXM1 function
log1p: ln(x + 1), known on Hewlett Packard Calculators as the LNP1 function
jn: Bessel Function of the First Kind, with x on the y-stack and the order n on the x-stack. jn also returns the Bessel Function of the Second Kind.
quad: Takes three arguments from the stack (a, b, c of ax^2+bx+c) and returns the real roots.

If you want to access the hyperbolic functions, you will need to call the Math and Hyperbolic calculator.

Memory

The calculator has 27 memories: memories a through z, and a special register ra. Storage and recall arithmetic can be performed on register ra - no idea why (except for maybe programming limitations) CalcFxC decided to restrict this feature to one register.

Programmability in the Form of Customizable Calculators

CalcFxC does not offer "traditional" macro or program capability. Instead, CalcFxC offers the ability to edit and create custom keyboards. You can redefine the key's name and help screen, along with it's formula. You have access to all of the functions. To use the stack arguments, use rgx(), rgy(), rgz(), and rgt() for the x, y, z, and t stacks respectively. This is a fun feature for those who has ever wanted to design their own calculators, and I am one of them!

To emulate the stack operations properly, you will need to define the formulas for each stack.

For example, if I designate the comb function as the Combination function, I would use the following formulas:
x Formula: combin(rgy(),rgx())
y Formula: rgz()
z Formula: rgt()
t Formula: rgt()
Last x Formula: rgx()

Functions can be copied and pasted. You will need some experience with RPN calculators to take advantage of this feature.

Final Word

This app is enjoyable to use. I am probably going to spend an afternoon or evening making a custom calculator. RPN fans, this is a good calculator app to get.

Since I am not a fan of ads, I will pay the \$0.99 to get the non-ad version.

4.5 of 5 stars.

Eddie

This blog is property of Edward Shore. 2012.

#### 1 comment:

1. This is a very nice article on calculator .i like your article.

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