表达式3: StartRoot, left parenthesis, "x" minus "a" , right parenthesis squared plus left parenthesis, "y" minus "b" , right parenthesis squared , EndRoot equals StartFraction, "s" Over cos left parenthesis, mod left parenthesis, left parenthesis, arctan left parenthesis, StartNestedFraction, "y" minus "b" NestedOver "x" minus "a" , EndNestedFraction , right parenthesis plus StartNestedFraction, pi left parenthesis, 1 minus sign left parenthesis, "x" minus "a" , right parenthesis , right parenthesis NestedOver 2 , EndNestedFraction , right parenthesis , StartNestedFraction, 2 pi NestedOver "n" , EndNestedFraction , right parenthesis minus StartNestedFraction, pi NestedOver "n" , EndNestedFraction , right parenthesis , EndFractionx−a2+y−b2=scosmodarctany−bx−a+π1−signx−a2,2πn−πn
