How can I solve an "indefinite reference"?

Question

I’m starting now in this life of programmer and I’m trying to perform a program for physics class but at the time of compiling the file is turning me this message... reach. c:(.text+0x68): undefined reference to cos' alcance.c:(.text+0x93): referência indefinida parasin' collect2: error: Ld returned 1 Exit status

I’m using Emacs... gcc -lm -o range. c, I must send other information??

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This is the part referring to consseno and sine Rx=0.0; Ry=0.0; vx=v0*cos(theta*3141592/180.0); Vy=v0*sin(theta*3.141592/180.0);
I must do the double cos, and double sin?

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#include <stdio.h>
#include <math.h>
 main () 
{
  double ry;
  double rx;
  double vx;
  double vy;
  double ax;
  double ay;
  double dt;
  double t;
  double g;
  double v0;
  double theta;
  double b; // [1/ms]coeficiente de arrasto
  double  dtheta; // angulo de lancamento

  g=-10;
  dt=0.1;// 
  v0=100;// velocidade inicial
  dtheta=1;// angulo de lançamente
  b=1;// coeficiente de arrato
  for (theta=0;theta<=90;theta=theta=dtheta){
    rx=0.0;
  ry=0.0;
  vx=v0*cos(theta*3141592/180.0);
  vy=v0*sin(theta*3.141592/180.0);

  
 for(t=0;t<=500;t=t+dt){

   if(ry<0.0)break;
   ax=0.0-b*vx;
   ay=-g-b*vy;
   rx=rx+vx*dt;
   ry=ry+vy*dt;
   vx=vx=ax*dt;
   vy=vy+ay*dt;
 }
#include <math.h>
 printf("%f %f %f %f %f %f\n",theta,t,rx,ry,vx,vy);
  }  
  return 0;
}

Answer 1

Put libraries at the end of the command

gcc -o alcance alcance.c -lm

According to the gcc manual

[...] It makes a Difference Where in the command you write this option [...]