Proposals of math codes. Area polygon. Vertices rectangle. Linear regression. Decimal IP

Juan_Antonio · November 10, 2019, 10:32am

2.- Given height, width and angle alfa of a rectangle, find coordinates of vertices.

Solution with extension:

p150_extension_GeoVertice.aia (21.5 KB)

Juan_Antonio · November 10, 2019, 10:32am

3.- Calculate the ecuation Linear Regression of n points.

lineal1

Example:
xValues = 10,20,30,40,50,60
yValues = 40,60,70,50,60,70

Linear regression: y = 0.37143 X + 45.33333

Information:
https://www.socscistatistics.com/tests/regression/default.aspx

Solution with extension:

p150_extension_linear.aia (14.0 KB)

Juan_Antonio · November 10, 2019, 10:33am

4.- Given a decimal number convert to IP.

Example:
Decimal = 3232241721

IP = 192.168.24.57

Convert decimal to IP online:
https://www.browserling.com/tools/dec-to-ip

Peter · November 10, 2019, 2:46pm

Nice examples showing the power of App Inventor.

Juan_Antonio · November 16, 2019, 3:08pm

5.- Evaluate the definite integral with an error less than 1‰
integral1

integral3
p84Ei_integrales.aia (1.9 KB)

apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 16, 2019, 4:02pm

6.- Adapt this code to App Inventor to get moon age.

http://www.primaryhomeworkhelp.co.uk/moon/hemispheres.html
fasesluna4

apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

////////////////////////////////////////////////////////////////////////////////
                //// CODE TO GET MOON AGE. Variable $jd //////////
///////////////////////////////////////////////////////////////////////////////
    $day = Read($Input1)
    $month = Read($Input2)
    $year = Read($Input3)

    $c = 0
    $e = 0
    $jd = 0
    $b = 0

    If ($month < 3) Then
    $year = $year - 1
    $month = $month + 12
    EndIf

    $month = $month + 1
    $c = 365.25 * $year
    $e = 30.6 * $month
    $jd = $c + $e + $day - 694039.09   ;  jd is total time

    $jd =  $jd / 29.5305882            ; divide moon cycle

    $b = Int ($jd)    
    $jd = $jd - $b                      ;  **$jd  is MOON AGE**
    $b = Round($jd * 8)                 

    If ($b >= 8 ) Then $b = 0
        
    Switch $b
    Case 0
        $fase = "Luna nueva"
    Case 1
        $fase = "Poco creciente"
    Case 2
        $fase = "Cuarto creciente"
    Case 3
        $fase = "Muy creciente"
    Case 4
        $fase = "Luna llena"
    Case 5
        $fase = "Poco menguante"
    Case 6
        $fase = "Cuarto menguante"
    Case 7
        $fase = "Muy menguante"
    EndSwitch

    GUICtrlSetData($Label5, $b & "-" & $fase)

Juan_Antonio · November 16, 2019, 4:29pm

7.- Solve two equations with two unknowns.

Verify:
http://www.1728.org/unknwn2.htm

dosecuaciones6

p84Di_dos_ecuaciones.aia (2.6 KB) (unfinished).

Juan_Antonio · November 16, 2019, 6:19pm

8.- Trigonometric projections of sine and cosine.

Drag your finger over the circle and get the horizontal and vertical projection of the radius.

radius = Canvas1.Width / 2

Verify:
https://www.geogebra.org/m/bvWJSh2n

p7Yi2_proyecciones.aia (4.0 KB) (unfinished).
apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 16, 2019, 10:16pm

9.- Calculates the linear equation given two points.
recta2

apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 17, 2019, 12:04am

10.- Draw the Archimedean spiral.

r = a + b*θ

Let
a = 5
b = 4
θ in radians. Five 360º turnings.

p84Gi_espiral_arq.aia (2.3 KB) (unfinished).
apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 17, 2019, 1:55pm

11.- Using a Clock with a TimerInterval of 4 seconds, 7-bit digital random numbers are presented on a Label.

The user must click on the Button_0 or Button_1 to add the parity bit (even).
A Label shows whether the user's response is correct or not.
The number of bytes created and the number of correct answers must also be displayed.

p91i_crear_bit_paridad_juego.aia (3.5 KB) (unfinished).
apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 23, 2019, 12:01pm

12.- Pully on an incline with friction.

A 5 kg mass is placed on an incline with friction. Making an angle of 30 degrees with the horizontal. A rope is attached and positioned over a pulley at the top of the incline. A 6 kg mass is suspend from the free end. What is the acceleration of the system.
m1 going up or down?
Assume µ = 0.20

Information: https://www.youtube.com/watch?v=Fek9Pa2jQio
apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 23, 2019, 12:03pm

13.- Uniform Rectilinear Motion.

A green car starts and maintains a speed of 90 km/h in a straight line.
Another red car located 24 km, starts 2 hours later at a speed of 120 km/h
Calculate how long it will take to reach the green car.

Information: https://ekuatio.com/en/uniform-rectilinear-motion-solving-problems-step-by-step/
apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 23, 2019, 12:35pm

14.- Find the inverse of a given number.
Show number and result with multiples and submultiples prefix.

Information: https://www.medcalc.org/manual/decimal_multiples_and_submultiples_of_si_units.php
apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 23, 2019, 4:25pm

15.- Find the impedance and phase angle of a circuit RLC.

Information: https://www.youtube.com/watch?v=IVS-vjHdC1c
apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 23, 2019, 9:19pm

16.- Wheatstone bridge.
a) Create a random value for Rx.
b) Move the Slider until the volts are approximately zero.
c) Now Rx = R * (R2 / R1)

Information: https://www.youtube.com/watch?v=VbiOLkhQC4w
Information: https://en.wikipedia.org/wiki/Wheatstone_bridge

p82Ii_wheatstone.aia (18.4 KB) (unfinished).
apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · November 30, 2019, 2:16pm

17.- Limit of a function. Evaluate expression. Parse mathematical expressions.

To evaluate an algebraic expression we can use:

a) JavaScript: http://kio4.com/appinventor/168_javascript_evaluar_expresion.htm

b) JavaScript: https://groups.google.com/forum/#!category-topic/mitappinventortest/specific-programming-issue/0oVTthDFChY

c) Math extension by Taifun: https://puravidaapps.com/math.php

...but the proposal is to calculate the limits of these functions using only blocks.

Example:

... when approaching value is 5, we can let x = 4.99999 or 5.00001

Information: https://www.mathwarehouse.com/calculus/limits/limits-indeterminate-factorable.php
Verification: https://www.dcode.fr/limit
Examples: https://www.matesfacil.com/BAC/limites/ejercicios-resueltos-limites-1.html

p78D_limites.aia (2.4 KB)

Juan_Antonio · November 30, 2019, 4:44pm

18.- Find the prime factors of a number.

primos_factores4

Verification: https://www.dcode.fr/prime-factors-decomposition
apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Juan_Antonio · December 5, 2019, 1:36pm

19.- Statistical.

In a class of 18 students, they have obtained the following scores:
4,4,4,5,5,5,5,5,7,7,8,8,8,8,9,9,9,10.
Calculate the mean, variance and standard deviation of that distribution.

apk file in external link: http://kio4.com/appinventor/apk_archivos.htm

Italo · December 6, 2019, 4:08pm

What an excellent library of exercises! Thanks for sharing it!