Expression 4: "y" equals left parenthesis, tan "a" , right parenthesis times "x" left brace, 0 less than "x" less than cos "a" , right bracey=tana·x0<x<cosa
4
Expression 5: "y" equals left parenthesis, tan "a" , right parenthesis times "x" left brace, cos "a" less than "x" less than 0 , right bracey=tana·xcosa<x<0
5
Expression 6: "x" equals cosine ( "a" ) left brace, 0 less than "y" less than sin ( "a" ) , right bracex=cos(a)0<y<sin(a)
6
Expression 7: "x" equals cosine ( "a" ) left brace, sin ( "a" ) less than "y" less than 0 , right bracex=cos(a)sin(a)<y<0