这算是什么东西！！！

#include<math.h>

#include<stdio.h>

main()

{

double x,s;

printf("input number:/n");

scanf("%lf",&x);

s=sin(x);

printf("sine of %lf is %lf/n",x,s);

}

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/tmp/ccVehrG6.o: In function `main':

t1-2.c:(.text+0x32): undefined reference to `sin'

collect2: ld returned 1 exit status

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07年的书，11年的编译器，呜呜…………