mycroft holmes
Last Activity: 10 Years ago
Consider the fraction a/b. If it is not already in reduced form then consider the equivalent fraction x/y such that gcd(|x|, y) =1
Then bx + a(-y) = 0. Also, since gcd (|x|, y) =1, there exist integers m, n such m|x|+ny =1
If x>0, then mx – n(-y) =1 so that we can choose h=m, k=-y, r=n, s=-y
If x<0, then (-m)x -n (-y) =1 so that we can choose h = -m, k=-y, r=n, s=-y
Thus we can always find h,k,r,s satisfying the given conditions