Trigonometric expressions used calculations

Figure 3. Trigonometric expressions used in calculation of dwell. The helical wind angle is A. ...

Structural dependences of 4J(F1,F[) in propanic and allylic systems were recently studied by Barfield29 calculating, within the FPT-DFT approach, the FC term of such couplings. In propane Barfield carried out calculations for different values of the dihedral angles about the C3 C2 and C2 C3 bonds and for different values of the C3 C2 C3 internal angle. Using these calculated values he established a four-term trigonometric expression, which was then... 

The correct determination of/ depends largely on using the correct value of the eios angle. In light of the analysis of a coauthor [19], the value of 105 is equal to 105 35.8 . Assuming this 105 value and the occurrence of the unit cell proposed by Daubeny and Bunn [8], after calculation of values of trigonometric functions, the expression in Eq. (6) may be written in the form [19] ... 

This formula yields the angle A expressed in degrees, which requires the use of a trigonometric table or a calculator that is capable of determining the inverse tangent. 

---