How did you defeat solaris

First, I should tell you during Solaris, all three hedgehogs have 50 rings to start with. They are constantly losing them, especially when they are hit. In order to keep from killing one of them, you need to switch between them to help the other gain health. Switch between them whenever one of the other hedgehog regards their rings. The order of switching hedgehogs is Sonic-> Shadow-> Silver-> Sonic. The hedgehogs gain rings when not being used up to 50, but only at the same pace that they lose them. Do not switch through them as fast as you can.

At first, you can only attack with Super Silver, by catching the boulders Solaris throws at you, then throwing them back at it.

Next, (you will know when you have done enough damage) Only Super Shadow will be able to damage him. Charge your Chaos Spear, then throw them at him. Something similar that happened to Silver will happen to Shadow on the other arm.

Now you will use Super Sonic. Fly into Solaris at top speeds (I think you have to charge them up first).

Then is Solaris phase two. (Here is the best Sonic music EVER for a final boss) Now you can attack using any of the three super hedgehogs to defeat Solaris.

Hope this helped!