I have some trouble with the transistor!

Lets imagine I have a circuit which has a transistor. the base and collector of the transistor are connected to a 12v dc.
and the emitter is connected to the gnd.
at both, collector and emitter i have a capacitor connected.

I know that the input at the first capacitor (at base) is a sinusoidal wave and that the output of the second capacitor (at collector) is a vertical-stretched cosine wave... why do i get this kind of wave at the output?

and what will happen if i change the sinusoidal wave at the input as a square or triangle wave?

I really don't get it, would really appreciate if someone could explain me something.

 

First off, you neither your base nor your collector are connected to 12V. They are connected to these things called resistors. Those resistors are very important.

What level course is this? In particular, what analysis techniques are available to you at this point?

Why do you think the output is a cosine wave when the input is a sine wave?