Using Math Functions

[calvesmit at ig dot com dot br]

I'm trying to compile the code below, but I can't to do it! gcc always 
complain. 
could someone help me? Why my sistem seems not know about math functions 
althoug i use #include math.h inclusion. 
send any hint to calvesmit at ig dot com dot br, 'cause I'm not a subscribe of your 
list. 

**********CODE*********** 
#include <stdio.h> 
#include <stdlib.h> 
#include <math.h> 

int main(int argc,char *argv[]) 
{ 
	int i; 
	if(argc==2){ 
		i=atoi(argv[1]); 
		printf("sin(%i)=%0.2f\n",i,sin(i));} 
	return 0; 
} 


**************ERROR MESSAGE************* 
$gcc sin.c -osin 
/root/tmp/ccpbz3XU.o: In function 'main': 
/root/tmp/ccpbz3XU.o(.text+0x32): undefined reference to 'sqrt' 
collect2: ld returned 1 exit status 

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