3 t ( 2 ) t ( 1 ) − 4 t ( 1 ) − 4 t ( 2 ) + 3 t ( 1 ) t ( 2 ) {\displaystyle {\frac {3t(2)t(1)-4t(1)-4t(2)+3}{{\sqrt {t(1)}}{\sqrt {t(2)}}}}}
