Expression 15: 90 minus tangent to the negative 1st power StartFraction, "E" Subscript, 2 , Baseline Over "E" Subscript, 1 , Baseline , EndFraction plus tangent to the negative 1st power StartFraction, "D" Subscript, 1 , Baseline minus "E" Subscript, 1 , Baseline Over "E" Subscript, 2 , Baseline , EndFraction equals 4590−tan−1E2E1+tan−1D1−E1E2=45
15
Expression 16: "D" Subscript, 1 , Baseline equals "E" Subscript, 2 , Baseline tangent left parenthesis, tan to the negative 1st power StartFraction, "E" Subscript, 2 , Baseline Over "E" Subscript, 1 , Baseline , EndFraction minus 45 , right parenthesis plus "E" Subscript, 1 , BaselineD1=E2tantan−1E2E1−45+E1