Now lets deal with the x direction points in the y direction so we don't need to worry about it. So we have . expressing this using eqs. 1.12 and 1.13 we have or . That makes sense. The tension in the two strings are the same because the angles are the same. It would seem bizarre if this was not true.
Now the y direction. We have to include all the tensions, . But we know and . So that means that , or