So, who took the AMC?

[chickendude]

Originally Posted by lord_carbo

I would have AAA'd it, given my past history with discrete mathematics tests for minors and my current history of being a huge math nerd even in my spare time 8)

Little overconfident there? I have always been a huge math nerd as well, but time became an issue for me. I only got to problem 23.


@Shrimpy
I didn't get it on the test, but I figured it out later

Basically, between 0 and pi, the sine wave will repeat n times.
Each mini sinewave will intersect the regular sin(x) wave twice (once on the up and once on the down) unless the two waves become tangent to each other at a peak or trough.

You add up all the intersections with simple arithmetic series and then subtract the tangent exceptions. The two can potentially become tangent at pi/2 and 3pi/2
sin(nx) = 1 and x = pi/2 only when n = 1 + 4r
sin(nx) = -1 and x = 3pi/2 only when n = 1 + 4r

so whenever n = 1 + 4r, you have to subtract a pair from the big sum and you should get the answer