I need some help with this differential pair circuit, i'm frustrated because i dont even know how to start the calculations. The circuit is this:

So we need to do some previsions in order to confirm the results on practical class.

We have the following questions.

__Calculate:__

**1.**Differential Gain of circuit

**2.**Common mode gain

**3.**Cutoff frequencies of circuit

Sorry for my bad english... Can someone please help me?

Many thanks in advance!