I had not really used math.h that often until I needed some cos() and sin() , when I included it gcc came up with stupid errors. That made made me think and I wnat to know how to solve this problem.It was a simple program I wrote to help me with my Russian physics work , to do with 'optika'. Thanks ....

Do you have a question?

You need to add -lm to the command line of gcc when linking because the math library (libm) is separate from the libc. That should fix all of your problems (which I am betting are linker errors).

Thanks...