Finding the Best Angle for Pulling a Block of Mass M

[lax1113]

Homework Statement

What is the best angle to make pulling a block of mass M, possible with the least tension.
Friction is applied, the coefficient varies, does the coefficient change the angle? for which is which angle best...

The Attempt at a Solution

I solved Tension for two different equations T=(mg-F_n)/sin(0) and
T= (F_n*coefficient of friction)/cos(0)
but I haven't really gotten anywhere with it.

 

[Redbelly98]

Can you draw a force diagram, and then list all forces or force components in the horizontal and vertical directions? That is a good way to start a problem like this.