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Hi!!!

I have some doubt about the expression of the dipole-dipole interaction  because my textbook uses two different formulas and I don't understand why/the difference

The first expression that uses  for a dipole-dipole interaction is:

E(r,θ₁,θ₂,φ) = -  (μ₁μ₂) / (4pi ε₀ε r³ )   * [2cosθ₁cosθ₂ - sinθ₁sinθ₂cosφ ]

In the common situation we have:
E(r,0,0,φ)= -2μ₁μ₂/4pi ε₀ε r³

(case where the two dipole are parallel and in the same verse)


THEN it uses this formula:

E= μ₁μ₂ f(θ) / 4piε r³
f(θ)= 1-cos³θ
 
What is the difference between these 2 formulas??
And in the  second one what is  the angle θ ?? 

And this two formula,in the end,take at the same result?
For example I think that if θ=0pi in the second formula I get:

E= μ₁μ₂  / 4piε r³* 1   -  μ₁μ₂  / 4piε r³* (3*1)
E= -2 μ₁μ₂  / 4piε r³

Thanks