表达式6: left parenthesis, cos left parenthesis, "t" , right parenthesis , sin left parenthesis, "t" , right parenthesis , right parenthesiscost,sint
6
表达式7: left parenthesis, "r" Subscript, "x" , Baseline cos left parenthesis, "T" , right parenthesis , "r" Subscript, "y" , Baseline sin left parenthesis, "T" , right parenthesis , right parenthesisrxcosT,rysinT
7
表达式8: "T" equals arc tangent left parenthesis, StartFraction, "r" Subscript, "x" , Baseline Over "r" Subscript, "y" , Baseline , EndFraction tan left parenthesis, StartFraction, pi Over 6 , EndFraction , right parenthesis , right parenthesisT=arctanrxrytanπ6