Espressione 12: "y" Subscript, "l" "e" "f" "t" "s" "h" "i" "n" , Baseline equals sine left parenthesis, left parenthesis, StartFraction, pi squared Over 10 , EndFraction , right parenthesis sin left parenthesis, "n" plus StartFraction, 3 pi Over 4 , EndFraction , right parenthesis minus StartFraction, 3 pi Over 4 , EndFraction , right parenthesisyleftshin=sinπ210sinn+3π4−3π4