Smooth Rotation with Acceleration & Decceleration

Hi, I've been playing with Construct 2 and I need some help with my math.

In my game You tell a sprite to rotate to a specific angle.

When the sprite starts it speeds up until it reaches a max speed then slows down so it will not overshoot the desired angle.

I've tried anglelerp but it starts of instantly then slows down, so that doesn't work.

I think if I knew how to get the current turn speed and know how many degrees it would turn before it slows down to zero, then I could do the rest.

So if it's turn speed increases by 1/sec:

(Both these values start at 0)

Acceleration = 2

TurnSpeed AngleTurnedTo

2          2

4          6

6          12

8          20

10        30

12        42

14        56

16        72

18        90

20        110

So if I could know the equation for this. I think I could make it work.

Any help?

If the start and end velocity is zero then it can be done by accelerating the first half of motion and decelerating the second half by the same amount.

Here is a capx:

http://dl.dropbox.com/u/5426011/examples14/accel_deccel.capx

Thanks, but the start velocity is not always 0 the player could change when the sprite is turning.

Here is how I solved it before in CC:

http://dl.dropbox.com/u/5426011/examples14/turret2.capx

(velocity^2)/(2*acceleration) is the stopping distance.