表达式4: "y" equals StartFraction, 4 Over "x" , EndFraction left brace, 1 less than or equal to "x" less than or equal to 4 , right bracey=4x1≤x≤4
延伸到3D
4
表达式5: "y" squared plus "z" squared equals left parenthesis, 5 minus "x" , right parenthesis squared left brace, "y" cos left parenthesis, "a" , right parenthesis plus "z" sin left parenthesis, "a" , right parenthesis equals 0 , right bracey2+z2=5−x2ycosa+zsina=0
5
表达式6: "y" squared plus "z" squared equals StartFraction, 4 squared Over "x" squared , EndFraction left brace, "y" cos left parenthesis, "a" , right parenthesis plus "z" sin left parenthesis, "a" , right parenthesis equals 0 , right bracey2+z2=42x2ycosa+zsina=0
