# Math

posted by
**Mary**
.

With figure,

img19.imageshack.us/img19/2135/81gd.png

prove:

tan(x/2) = sin(x)/(1+cos(x)).

posted by
**Mary**
.

With figure,

img19.imageshack.us/img19/2135/81gd.png

prove:

tan(x/2) = sin(x)/(1+cos(x)).