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# tan (<valarray>)

Visual Studio 2013

Operates on the elements of an input valarray, returning a valarray whose elements are equal to the tangent of the elements of the input valarray.

```template<class Type>
valarray<Type> tan(
const valarray<Type>& _Left
);
```
_Left

The input valarray whose elements are to be operated on by the member function.

A valarray whose elements are equal to the tangent of the elements of the input valarray.

```// valarray_tan.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>
#include <iomanip>

int main( )
{
using namespace std;
double pi = 3.14159265359;
int i;

valarray<double> va1 ( 9 );
for ( i = 0 ; i < 9 ; i++ )
va1 [ i ] =  ( pi/2 ) * ( 0.25 * i - 1 );
valarray<double> va2 ( 9 );

cout << "The initial valarray is:\n";
for ( i = 0 ; i < 9 ; i++ )
cout << setw( 10 ) << va1 [ i ]
<< "     radians, which is   "
<< setw( 5 ) << ( 180/pi ) * va1 [ i ]
<< "   degrees" << endl;
cout << endl;

va2 = tan ( va1 );
cout << "The tangent of the initial valarray is:\n ";
for ( i = 0 ; i < 9 ; i++ )
cout << va2 [ i ] << endl;
}
```
```The initial valarray is:
-1.5708     radians, which is     -90   degrees
-1.1781     radians, which is   -67.5   degrees
-0.785398     radians, which is     -45   degrees
-0.392699     radians, which is   -22.5   degrees
0     radians, which is       0   degrees
0.392699     radians, which is    22.5   degrees
0.785398     radians, which is      45   degrees
1.1781     radians, which is    67.5   degrees
1.5708     radians, which is      90   degrees

The tangent of the initial valarray is:
9.6701e+012
-2.41421
-1
-0.414214
0
0.414214
1
2.41421
-9.6701e+012```