Pumping for CFLs

Use the pumping lemma to show the following are not CFLs

1.    strings of the form WcW where W is a string from (a,b)*

2. like above, but strings of the form WW

3.       {aⁿb^mc^k: n, m, k ³ 0 and m £ min(n, k)}.

4.    {ww^Rw : w Î {a, b}*}