式2: left parenthesis, "f" left parenthesis, 1.5 , right parenthesis minus "f" left parenthesis, 1 , right parenthesis , right parenthesis times 2 "x" minus 1.3 5f1.5−f1·2x−1.35
2
式3: 1.2 "x" minus 0.81.2x−0.8
3
式4: left parenthesis, "f" left parenthesis, 1.5 , right parenthesis minus "f" left parenthesis, 0.5 , right parenthesis , right parenthesis "x" minus 0 minus 0.6f1.5−f0.5x−0−0.6