tranleduy2000 / ncalc

Power calculator for Android. Solve some problem algebra and calculus.

Calculator N+ - Powerful calculator for Android.

Overview

This is a powerful android calculator that contains most of the features needed. The power of the application is through the use of the Symja library. The results are displayed by Latex. This project is an open source project that allows people to study, ad-free application.

Get lite version in Google Play Store

How to build this source by using Android Studio

1. Clone project, Select File->New->Project from Version Control->GitHub
2. Select and build module app

Screenshot

ALGEBRA

1. Computer science
2. Solving the equation:
3. Solve system equations
4. Graphing
6. Unit Conversions
8. Simplify expressions
9. Polynomial factorization.
10. Binomial expansion Newton
11. Matrix

ANALYTICS

1. Derivative
2. Antiderivative
3. Definite integrals
4. Find the limit of the sequence, function

TRIGONOMETRIC

1. Trigonometric expand: sin(2x) -> 2sin(x)cos(x)
2. Trigonometric reduce: 2sin(x)cos(x) -> sin(2x)
3. Trigonometric to exponent: sinh(x) -> (e^x-e^(-x))/2

DETERMINATION OF STATISTICS

1. Combination
2. Permutation

SOME OTHER FEATURES

1. Prime factors
2. Modulo
3. Catalan number
4. Fibonacci number
5. Pi number

Note

The Calculator does not show the steps to solve the equations, system of equations, derivative... but only for the final result. Enter Sin(30°) to calculate sine Degree mode

The computer can work in two modes:

• Decimal mode: 0.12312312323
• Mode fractions: for results with arbitrary precision, for example 9^99999

License GNU GPL 3.0

Any user re-publish this app on Google Play without open source project will be reported.

Copyright 2017 Tran Le Duy

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

ncalc's Issues

Dark mode shows result in black

Currently dark mode still shows results in black color, making it pretty unreadable. These input colors in themes should apply to output, too. (Maybe some CSS can be done to color the results?)

Ncalc shows wrong result

hello,
unfortunately sometimes ncalc shows a slightly wrong result.
E.G. subtract a value from another and the result should be a number with two digits right from decimalpoint. But ncalc shows a additional digit, though the result has more than two digits.
0,25 versus 0,25000000005.

Any clues?

Regards
Poul

Feature Reqeust: Orange Theme

Feature Request: Add Gestures (whipe)

Adding calculator to F-Droid

It would be amazing to see the calculator on F-Droid.

Degree/Radian

An easy switch for Degree and Radian mode

non-lite app uploaded here?

Dear @tranleduy2000 ,
It would be great,if you could upload the non-lite app here on github /or at the play store,since it is a great app, yet not everyone can afford a near-nuclear-power-plant pc, which has enough resource to be able to use and make the app out from the files, you have shared with us.
If someone had asked the same, then please ignore it.
Good luck developping such great apps like this!
Yours sincerely,
Cheeseman

Wrong answer

Enter this into equation solver:30*x/0.0002=30. It returns result x = 1.4365636569180902. When you add more zeros before 2, it also produces bad result. If you remove one zero, it produces good result.

I'm unable to find where the problem is, so at least I'm creating this issue.

Error in velocity conversion

Enter 30km/h, get result 30.0000...4km/h.

Deploy to F-Droid

Would you consider releasing your app on F-Droid as well for those who prefer it over Play Store?

log and ln are both calculated has ln

Their is a nasty bug: log and ln are both calculated has ln...

Integrals of absolute values don't work

If I use the Integrate menu to integrate the following, for example, from -1 to 1:

Abs(x^2-5)

It returns the integral, unevaluated. If I use e^x in it:

Abs(E^x-2)

for any domain, it thinks for a long time and then returns the unevaluated integral.

Unable to input minus sign in temperature conversion

Everything's in the title. Whether by using the keyboard key or pasting, it's impossible to add a - in front of the temperatures.

Feature request : auto-multiply when hit 10^x

If I mean for example 2e-3
I would expect to digit
2
10^x
-3
But using this combination I got 210^-2 instead.

Actually I need to digit a multiply sign before 10^x to have right result.

Feature Request: Buttons to navigate the equations

Of course you can touch the equation to jump to the desired location, but sometimes arrows are more convenient to go back one position, for example.
Maybe combine this with gestures? Wish to the left: go one position the the left?

Feture Request: currency conversion

I'd like to suggest adding a currency converter in the app.
The rates need to be updated periodically, like it was done in PalmCalc.

Feture Request: Always on / No sleep

Hi,

Would it be possible to add a feture where the display never sleeps? I hate it when im using my calculator and my display automatically turns off.

Result styling

The current implementation centers the result and renders in some Math-y serif font, which is not necessarily the most readable thing on screen. Ncalc should consider:

• Right-aligning the result
• Using a sans-serif for result (https://tex.stackexchange.com/questions/77932/the-right-way-to-get-sans-serif-math)

Additional issues include size and line-breaking, both of which appear not quite easy to address for now.

Themes are inconsistent

Hello,
I think it is overall a pretty app, even somewhat better than the built-in one (proper FAB, haha), but I noticed the themes are quite inconsistent:

• "Light" is exactly the same as "Cyan"
• Dark themes are mixed with light ones
• No accent color setting, you never know what you get
• "Gradient" only has one color
• Some elements have persistent colors

And here's how I think it could be fixed:

• "Light", "Dark" and "Gradient" as base options
• Separate color settings for primary and accent
• FAB should use the primary color (because secondary is already used in a large area)
• Advanced doesn't need to be there (#22)

Feature Request: Why not use long hold buttons?

I like the advanced Button on the lower edge,
but with the long hold buttons for accessing secondary function, this would greatly increase the accessibility or rather the user interface?
Maybe combine this with configurable buttons?

Feature request: arithmetic and geometric progressions

Do you find this type of calculation useful?

It would be useful to display,
Besides the elements in the sequence,
The partial sums

Like
Start = 0
Step = 1

0 1 2 3 4 5 6 7
0 1 3 6 10 15 21 28

Feature Request: Natural/Mathematical display

See Wikipedia for what I mean:
https://en.wikipedia.org/wiki/Calculator_input_methods#Mathematical_display
At least for divisions, roots and exponentiations.
This should be for the Input, the output already has this for divisions (you know.. the upper-right button)

Please allow user keyboard input.

I saw there are a lot of functions in All functions inside of menu, but how can I use these functions? I can't input these functions with my own keyboard like using Python, I can only use the in-app keyboard, which only contains limited functions, so there is no way to input a function manually.

Feature Request: Add setting to configure Button functions

Feature Request: Unit Prefix like M(mega),m(milli)

Unit prefix would be a nice feature to have

1. It would be implemented on long press a key to select the data modifier,like
   

ans always equals 0

I just installed NCalc+ on my Android and tested out different functions and was really happy how it worked until I noticed that any way I tried, the ans button would always equalled the number 0, no matter what I had executed before. I tried to restart and even reinstall to no avail.

Can i contribute a logo for ncalc?

Can i contribute a logo for ncalc?

Graph mode can not zoom.

After zoom in/out:
lag.
And the screenshot
https://1drv.ms/u/s!AkL-7NgRmjYBh5ZxbneJt5sNa7Dr8A

Xiaomi 5, gemini, 8.1.0 COS.

Numbers starting with decimal point not recognised after /

Thanks for the great calculator.

There seems to be a parsing bug in the scientific calculator view - the following doesn't work:
1/.5
It works ok with:
1/0.5
1/(.5)
The other basic operators + - × don't seem have the same problem.

One of virustotal results reports that app contains TrojWare.JS.Agent.ANI

https://www.virustotal.com/en/file/03D4414042CA2975044816C846E16213CDE674D77AD42A18A6CF1ABDA342835C/analysis/

Unit name & conversion factor

Two small things:

• The Unit of Energy is called "Joule" and not "Jun". Interestingly you used the internal name energyunitjoules. And I also never saw Jun as some sort of abbreviation for Joule (neither in German nor in English)
• The conversion from Celsius to Kelvin is -273.15 and not -273. Btw. are negative numbers even possible to enter?

P.S. contact me if you want a german localization for your program

Back navigation is non intuitive

When you open different views using the navigation drawer and then press back, it plays back the stack of previously opened views. This was unexpected for me since since I expect the back button to navigate out of the app rather than go back. I think the Android way of doing this in such a master detail layout is to not add the transactions to the back stack. But correct me if I am wrong.

Feature request: int(x), frac(x), floor(x) functions?

I tried to create a new function
Modc(x) = mod(x, 360)

But doesn't work.
Either i did a mistake,
Or only basic functions can be used when defining a new function.

If only basic functions are permitted,
Then these 3 functions should be added.

Also an if() function should be useful,
But maybe there's one, and i missed it.

Perm and Comb are calculated incorrectly

Please check on Wolfram Mathworld for the definitions of these calculations:

Binomial coefficient: http://mathworld.wolfram.com/BinomialCoefficient.html
Factorial (you've done it right): http://mathworld.wolfram.com/Factorial.html

In particular, two things are wrong:

1. You shouldn't round off the numbers before you apply the factorial (or gamma) function.
2. When the result shows indeterminate, it should be actually zero sometimes. (The factorial/gamma function returns "indeterminate" because it reaches infinity. When a finite number is divided by that infinity, it becomes zero. And this is in line with the fact that nCr=0 when n, r are integers, r < 0 or r > n.)

Feature request: arbitrary bases

Instead of just decimal, octal, binary, and hexadecimal, it would be nice if you could use any base below 16, say, base 6 or 12.

Opening Prime Number after Catalan Number does not change the content

Expected behaviour

There is a group of tabs in the navigation sidebar (Catalan Number, Prime Number, Divisors, Fibonnaci Number). Switching from one tab to another should be doable without any issue.

Actual behaviour

The attempt of switching from one to another in the named group fails as the content does not change. Another tab of the group can be opened only if the app is closed and opened again.

Steps to reproduce

1. Select Prime Number from the navigation sidebar
2. Select Catalan Number
3. The content does not change, the Prime Number is selected and shown

You can repeat the steps with any of the tabs from the group listed above.

• Android 7.1.1
• version 3.4.0

Some themes make some UI text difficult to read

Some themes in the app make it very difficult to read. Below is a breakdown of the themes and their issues.

Results are difficult to read in

• Dark
• Brown
• Purple
• Deep Purple Teal

The use of black font on a grey background causes this.

Function buttons are difficult to read in

• Red

The use of white font on a yellow background causes this.

Example images

Dark results text (theme: Dark)

Light function text (theme: Red)

Top bar removal

Hi!
Your app is really good as an Material Design CAS app alternative for math studio and it's really happy to see that it is open source. I like the app and appreciate your effort very much.

But from the perspective of Material Design, it is not that proper to put a top bar on the hamburger menu (screenshot below).

Is it possible to remove it in the next version? Thanks!

Hint and keyboard button not working in section in the application

Expected behavior

The hint and keyboard button is meant to work in all sections, as long as it is being placed there.

Actual Behavior

While clicking on hint and keyboard, in some section of the application it does not work at all, such as the combination and permutation section.

How to reproduce

• Download and install the application
• Lunch the application
• Click on the menu on the top right side
• Scroll to the probability statistics category
• Select Combination
• Click on the hint and keyboard button

Discover that it is not working

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Application version: 3.4.0
Operating system: Android v7.0

Recording Of The Bug

https://youtu.be/8ES9NMj4Udg

Feature Request: Simple Interest Calculator

Performing a particular mathematical operation caused the app to initially freeze and then crash

Expected behavior

The calculator should be able to perform calculating operations within it's limit without any hassle.

Actual behavior

When I tried to perform the operation 10^3 three times, the calculator initially froze and then eventually crashed when I tried pressing other inputs to abort the operation.

How to reproduce

• launch the calculator
• turn on fraction mode which is indicated by A/B on the top right of the calculator
• try to perform the operation 10^3 three times and the app freezes on the third time.

PS: For single unit number eg 1-9, the app freezes the fourth time. Also this is only reproducible when the fraction mode is switched on.

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• Browser/App version: Ncalc+|| v 3.4.0
• Operating system: Android 7.0

Recording Of The Bug

https://youtu.be/S5A8QxukLgw

GPE and GKE calculations

A relatively minor addition to the app I would like to see is the ability to have gravitational (or any other for that matter) potential and kenetic energy calculations done. I'm rather busy right now but if I can I'll try and figure out how to add them to the project.

Language error

In 2D Cartestiam Geometry, Vector perpendicular, text is not written in English. Seems like no one has spotted this out, I'm not sure if it's my device's problem or the app's.

Bases buttons in Base-N Calc don't get highlighted when selected

Hi,

So the buttons that allow you to select in which base to operate with ("Dec", "Hex", "Bin" and "Oct") don't get highlighted when you select them. The calculator changes it's base correctly, but the "Dec" button keeps highlighted no matter what you do. Simple design bug but may be annoying.

Flat Icon

It's not an important improvement but would be cool change the app's icon with a new one more flat.

Chinese language option not responding

Expected behavior

Language of the Ncalc+ app should change to Chinese (Simplified) when chosen as the preferred language

Actual behavior

I changed the language of the application to Chinese (simplified), it keeps displaying English language instead of Chinese simplified characters

How to reproduce

Download Ncalc+ (open source) from the google play store, open the app, go to settings, use the language options, change it to Chinese (simplified), it will only display English not the selected language

• Browser: Ncalc+
• Operating system: Android Nougat 7.0
• Phone: Tecno Camon CX air

Recording Of The Bug

https://youtu.be/GKK3G9Q_39A

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Posted on Utopian.io - Rewarding Open Source Contributors

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Improve Advanced

"Advanced" is a section that contains items that are not often used, however

• the panel grip header is very in-the-face with its color
• the grip header takes up a big area of the UI, especially on small devices
• the panel when expanded is inconvenient, as it covers up every other button - lots of back-and-forth expanding required for usage

As a simple solution I suggest making the scientific panel on the top of the keypad left-right scrollable, with three pages of buttons.

Derivative: Wrong answer

When trying to derive the function: (x+2)/(x-3) the answer I get when using this calculator is: (-3+x)^-1 + (x-2)/(3-x)^2 which later results to the following answer: (2x−5)/(3-x)^2 and that is the wrong answer for the first derivative of this function. The correct answer for the first derivative of the this function should be: (5)/(x-3)^2

Can you activate history in IDE mode

Can you please activate the % character to get the last evaluated result in IDE mode (Version > 3.4.1)

At the moment the input returns Out(-1)

Issue? 2d geometry, straight line

Giving
A = 0,0
B = 10,0

AB length = 14.14
Midpoint = 5,5
?!
I presume it's a bug

Then,
How can we give negative numbers?

• (minus button) doesn't work

Also issues when giving CD line
Intersection is not right
A = 0,0
B=10,10
C=0,10
D=10,0
Gives intersection 10,10