How do I convert a decimal value of a degree?

kappter

I am trying to take the decimal value of adjacent/hypotenuse and convert it to a degree i.e.

 [cos^-1(0.1827)] = 79.5

How do I code cos raised to -1 etc...

kappter

void setup() {
  size(530,600);
  background(255);
}

void draw() {
  background(255);
  stroke(0);
  strokeWeight(4);
  noFill();
  if(mouseX<200) {
    //triangle(0, 0, 150, 0, 150, mouseY);
    stroke(255,0,0);
    line(150,0,150,mouseY);
    stroke(0,0,255);
    line(0,0,150,mouseY);
    stroke(0,100,0);
    line(0,0,150,0);
    drawLeftReference(mouseY);
    text("A",135,mouseY+10);
    text("B",20,15);
  } else if(mouseX>200) {
    //triangle(350,0,500,0,350,mouseY);
    stroke(0,0,255);
    line(500,0,350,mouseY);
    stroke(255,0,0);
    line(350,0,350,mouseY);
    stroke(0,100,0);
    line(350,0,500,0);
    drawRightReference(mouseY);
    text("A",355,mouseY+10);
    text("B",505,15);
  }
}

void drawLeftReference(float yValue) {
  stroke(0);
  strokeWeight(1);
  line(135,0,135,15);
  line(135,15,150,15);
  text("Triangle Reference", 165,15);
  fill(0,0,255);
  text("Hypotenuse = " + findHypot(mouseY), 165,35);
  fill(255,0,0);
  text("Adjacent = " + mouseY, 165,55);
  fill(0,100,0);
  text("Opposite = " + 150, 165,75);
  fill(0);
  text("Angle A = " + exp(-1*cos(yValue/findHypot(mouseY))), 165,95);
  text("Angle B = " + 150/findHypot(mouseY), 165,115);
}
void drawRightReference(float yValue) {
  stroke(0);
  strokeWeight(1);
  line(350,15,365,15);
  line(365,0,365,15);
  text("Triangle Reference", 165,15);
  fill(0,0,255);
  text("Hypotenuse = " + findHypot(mouseY), 165,35);
  fill(255,0,0);
  text("Adjacent = " + mouseY, 165,55);
  fill(0,100,0);
  text("Opposite = " + 150, 165,75);
  fill(0);
  text("Angle A = " + yValue/findHypot(mouseY), 165,95);
  text("Angle B = " + 150/findHypot(mouseY), 165,115);
}

float findHypot(float yVal) {
  yVal = sqrt((150*150)+(yVal*yVal));
  return yVal;
}

asimes

Please format your code before pasting. You can do that with Command+t.

If I understand your question, you have an angle that you want in degrees. The trig functions use radians and can be converted with degrees(): http://processing.org/reference/degrees_.html

koogs

no, i think he just wants the arccos function name:

http://processing.org/reference/acos_.html

see also http://processing.org/reference/asin_.html and http://processing.org/reference/atan2_.html

(atan2() is recommended over atan())

kappter

I tried degrees() and its close, must have something off...

void setup() {
  size(530,600);
  background(255);
}

void draw() {
  background(255);
  stroke(0);
  strokeWeight(4);
  noFill();
  if(mouseX<200) {
    //triangle(0, 0, 150, 0, 150, mouseY);
    stroke(255,0,0);
    line(150,0,150,mouseY);
    stroke(0,0,255);
    line(0,0,150,mouseY;)
    stroke(0,100,0);
    line(0,0,150,0);
    drawLeftReference(mouseY);
    text("A",135,mouseY+10);
    text("B",20,15);
  } else if(mouseX>200) {
    //triangle(350,0,500,0,350,mouseY);
    stroke(0,0,255);
    line(500,0,350,mouseY);
    stroke(255,0,0);
    line(350,0,350,mouseY);
    stroke(0,100,0);
    line(350,0,500,0);
    drawRightReference(mouseY);
    text("A",355,mouseY+10);
    text("B",505,15);
  }
}

void drawLeftReference(float yValue) {
  stroke(0);
  strokeWeight(1);
  line(135,0,135,15);
  line(135,15,150,15);
  text("Triangle Reference", 165,15);
  fill(0,0,255);
  text("Hypotenuse = " + findHypot(mouseY), 165,35);
  fill(255,0,0);
  text("Adjacent = " + mouseY, 165,55);
  fill(0,100,0);
  text("Opposite = " + 150, 165,75);
  fill(0);
  text("Angle A = " + degrees(150/findHypot(mouseY)), 165,95);
  text("Angle B = " + degrees(yValue/findHypot(mouseY)), 165,115);

}
void drawRightReference(float yValue) {
  stroke(0);
  strokeWeight(1);
  line(350,15,365,15);
  line(365,0,365,15);
  text("Triangle Reference", 165,15);
  fill(0,0,255);
  text("Hypotenuse = " + findHypot(mouseY), 165,35);
  fill(255,0,0);
  text("Adjacent = " + mouseY, 165,55);
  fill(0,100,0);
  text("Opposite = " + 150, 165,75);
  fill(0);
  text("Angle A = " + degrees(150/findHypot(mouseY)), 165,95);
  text("Angle B = " + degrees(yValue/findHypot(mouseY)), 165,115);

}

float findHypot(float yVal) {
  yVal = sqrt((150*150)+(yVal*yVal));
  return yVal;
}

koogs

degrees just converts from radians to degrees, a simple multiplication.

you want acos() etc, which are what you're calling cos^-1

http://en.wikipedia.org/wiki/Inverse_trigonometric_function

koogs

(^ answer will be in radians)

quark

This might make it clearer

float angRads = acos(0.1827);
float angDegs = degrees(angRads);
println(angDegs);

will display 79.47293

kappter

Thanks... thats it!