Computational language theory proof

[sbc824]

Homework Statement

I need to prove this

http://www.freeimagehosting.net/newuploads/66exd.jpg

R represents the reversal of...L1 and L2 represent languages, which can represent strings.

(L1L2) = the concatenation of L1 and L2

Ex.

L1 = 01001
L2 = 001

L1L2 = 01001001
(L1L2)^R = 10010010

The Attempt at a Solution

Let y be a member of E* denote an arbitrary string in the set (L1L2)^R.

This is where I'm stuck...

 

[HallsofIvy]

Homework Statement

I need to prove this

http://www.freeimagehosting.net/newuploads/66exd.jpg

R represents the reversal of...L1 and L2 represent languages, which can represent strings.

(L1L2) = the concatenation of L1 and L2

Ex.

L1 = 01001
L2 = 001

L1L2 = 01001001
(L1L2)^R = 10010010

And what is L2^RL1^R? That seems the obvious thing to calculate to see what the question is asking.

The Attempt at a Solution

Let y be a member of E* denote an arbitrary string in the set (L1L2)^R.

This is where I'm stuck...