calculate angles

Tamino

Hi, i have the following question: i have a triangle with a 90° angle and want to calculate Alpha. How can I do this? Please help me

mschi

http://processing.org/tutorials/trig/

asimes

I diagram would be helpful, not sure what alpha in the context of a right triangle

Tamino

i found this too, but i want to calculate an angle, what they don't do in this tutorial...

RoryJMcEwan

Depends what you have: how many sides and angles you know.....

RoryJMcEwan

If you have 3 angles (which I'm guessing you don't) you do CosX=a^2+b^2-2abCosC. If you have at least an angle and a side and 2 others, if you post them and I'll tell you what to do (it's a bit complicated to explain). :) Hope I can help

shadabk92

If a diagram is not a comfortable method to explain a problem, you could explain it taking some other example or in simple words.

This link shows the basic needs you might need to fulfill http://processing.org/tutorials/trig/

Shadab K

Weave and Connect

mschi

oh yes. i see. sorry.

but checkout this chapter of the the nature of code book: http://natureofcode.com/book/chapter-3-oscillation/

especially chapter 3.4

Chrisir

In my opinion this question is not solved in the tutorial

here...

int angle; 
int radius = 70;

int centerX=200;
int centerY=200;


void setup() {
  size(700, 700);
  background(110);
}

void draw() {
  background(110, 11);

  float moveX = radius * sin(radians(angle))+centerX;
  float moveY = -radius * cos(radians(angle))+centerY;

  float moveX2 = radius * sin(radians(angle))+0;
  float moveY2 = -radius * cos(radians(angle))+0;

  float angle2 =   atan2(moveY2, moveX2);

  angle2 = map (angle2-HALF_PI, -PI, PI, 
  0, TWO_PI);

  // white point 
  stroke(255);
  fill(255, 2, 2);
  point(moveX, moveY);

  // 2 green lines 
  stroke(0, 111, 0);
  line (moveX, centerY, centerX, centerY);
  line (centerX, centerY, centerX, moveY);

  // display text : angle 
  fill(110);
  noStroke();
  rect (width-200, height-200, 200, 200);
  fill(0);
  stroke(0);
  text ("angle: " 
    + angle + "\n"
    + moveX+","
    + moveY, width-100, height-100);


  print(angle +", ");
  float result=degrees(angle2)+0; 
  if (result<0) 
    result=result+360;
  int result2 = int (round(result));
  if (result2!=  angle) 
    print ("wrong: ");

  println(result2);

  // increase 
  angle++;
}

Chrisir

my solution uses opposite side and adjacent side (between those is the right angle) to calculate the angle named θ

see the tutorial, 1st image, for these namings I use

http://processing.org/tutorials/trig/

Chrisir

my solution is not short nor elegant...