Find the value of sin 0
cos(90°- 0) + cos 0 sin(90°-0)

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

He will need 2,898 pieces of paper