Problem using tan() and cos() functions

I have a small bit of code that should accept an input as a double and use that input value in an equation with tan() and cos()...but it doesn't work and I don't know why. Here's my code:

Code:

#include <stdio.h>
#include <math.h> 

int main (void)
{
        double theta = 0.0, sin_theta = 0.0;

    printf ("Enter a number (theta) to be calculated: ");
    scanf ("%lf", &theta);
    sin_theta = (tan (theta)) * (cos (theta));
    printf ("Tangent of theta times cosine of theta: %lf\n\n\n", 
                 sin_theta);

        return 0;
}

Any help is welcome. Thanks!

What do you input to the program, and with this input what output does the program produce? What output do you expect? Also note that tan() is based on radians.

Jim

Oh, I see my problem! I was checking the math with WolframAlpha and it assumed the values I plugged in were degree values. Turns out my code works! Thanks for the reminder about the radians.