{{keywords>wiki library source code example reference}}
===== tan =====
<code cpp>
    double tan(double);
</code>
Returns the tangent of a radian angle x. 


===== cpp Sourcecode Example =====
<code cpp>
#include <iostream> /* including standard library */
#include <cmath> /* including math library */

using namespace std;
int main( void )
{
    double x;
    x = 42;
    
    //cout.setf(ios::fixed, ios::floatfield);
    cout.precision(8);

    cout << "tan of " << x << "° is " << tan (x*3.1415/180) << endl;
    return 0;
}
</code>

==== output ====
    tan of 42° is 0.9003649