Expression 4: cosine to the negative 1st power StartFraction, "s" squared plus "s" squared minus "S" squared Over 2 times "s" Subscript, 1 , Baseline times "s" Subscript, 8 , Baseline , EndFraction equals alphacos−1s21+s28−S22·s1·s8=α
4
Expression 5: "S" equals StartRoot, "s" squared plus "s" squared minus 2 times "s" Subscript, 1 , Baseline times "s" Subscript, 8 , Baseline cos alpha , EndRoot equals 3.6 0 5 5 5 1 2 7 5 4 6S=s21+s28−2·s1·s8cosα