I'm trying to make a program which you choose an angle I'm trying to make a program which you choose an angle, and it tells you it's respective Sin, Cos and Tan. But, I can't figure out why all of the angles I use have the same answer (Sin 0, Cos 1 and Tan 0. Can someone help me out?

#include &lt;math.h&gt; 
double angulo;
double seno;
double cosseno;
double tangente;
double rad;
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
}

void loop() {

 Serial.println("Programa para calcular sen, cos e tg");
 delay(1000);
 Serial.println("Digite o angulo");
 angulo = Serial.parseInt();
 rad = angulo*0,0174533;
 seno = sin(rad);
 Serial.println("Seno");
 Serial.println(seno);
 cosseno = cos(rad);
 Serial.println("Cosseno");
 Serial.println(cosseno);
 tangente = tan(rad);
 Serial.println("Tangente");
 Serial.println(tangente);

}
You have written

rad = angulo*0,0174533;


But, C++ uses the american decimal notation:

rad = angulo*0.0174533;


Thus, you have been multiplying angulo by zero every time.