If p^→ = ((a),(b) ) and q^→ = ((c),(d) ),
Prove that the area bounded by
p^→ ,q^→ and p^→ −q^(→ ) is (((ad−bc))/2).
Hints: Use cosine rule and sine rule
Find the number of rational numbers
r, 0<r<1, such that when r is written
as fraction in lowest term. The
numerator and demominator have a
sum of 1000.