How do I create line from equation ?

Hello ! I'm making a minigolf game and I stuck on a feature I want to add.

The feature is a dotted line who show the curve the ball will browse. Like it implemented in Angry Birds.

I have no idea how can I start doing it, I success to create a line between to points but it doesn't represent the real curve.

How implement it ?

https://www.desmos.com/calculator

Then start fiddling with the math until you get what you are wanting.

Try plugging this in:

-\frac{x^2}{15}+6

Here's one way:

Proxyma

Here is a similar approach I took to create an angry bird type game. The farther you pull back on the slingshot, the more velocity you give the projectile... it plots a dotted line to show where the bird will go.

http://www.rieperts.com/games/forum/angry_birds.capx