# For Monday, February 6th

For Monday:

Proof for Feedback

Combinatorial Proof

3. Consider the binomial coefficients ${{n}\choose{k}}$ and ${{n}\choose{n-k}}$.  Check for n=4 and k=1 that these are equal.  Using the formula for the binomial coefficient (last theorem in last class) to show that these are equal (for all 0 <= k <= n).  Use a counting argument (combinatorial proof) to show that these are equal (for all 0 <= k <= n).