Expression 3: "y" equals StartFraction, 1 Over "a" , EndFraction left parenthesis, arctan left parenthesis, StartFraction, "x" Over "a" , EndFraction , right parenthesis minus StartFraction, pi Over 2 , EndFraction sgn left parenthesis, StartFraction, "x" Over "a" , EndFraction , right parenthesis , right parenthesis Has graph. To audio trace, press ALT+T.y=1aarctanxa−π2sgnxa
3
Expression 4: "y" equals negative "a" left parenthesis, StartFraction, 1 Over tanh left parenthesis, "a" "x" , right parenthesis , EndFraction minus sgn left parenthesis, "a" "x" , right parenthesis , right parenthesis Has graph. To audio trace, press ALT+T.y=−a1tanhax−sgnax