Putnam Practice Problems V (PPPV)


1.

Evaluate


2.

Let p(x) = 2+4x+3x2+5x3+3x4+4x5+2x6. For k with 0 < k < 5, define

For which k is Ik smallest?


3.

Consider all lines which meet the graph of y = 2x4+7x3+3x-5 in four distinct points, say (xi,yi), i = 1,2,3,4. Show that

is independent of the line and find its value.


4.

Let z = x+iy be a complex number with x and y rational and with |z| = 1. Show that the number |z2n-1| is rational for every integer n.


5.

Evaluate the double series


6.

Let

be a polynomial of degree n with integral coefficients. If a0, an and f(1) are odd, prove that f(x) = 0 has no rational roots.


Good luck everybody!