ab-cd
Source:
March 23, 2008
trigonometrycomplex numbers
Problem Statement
Suppose that are real numbers satisfying , a^2 \plus{} d^2 \equal{} 1, b^2 \plus{} c^2 \equal{} 1, and ac \plus{} bd \equal{} 1/3. Find the value of ab \minus{} cd.
Source: