Expression 9: StartFraction, left parenthesis, "f" left parenthesis, "a" plus "b" , right parenthesis minus "f" left parenthesis, "a" , right parenthesis , right parenthesis Over left parenthesis, "a" plus "b" , right parenthesis minus "a" , EndFractionfa+b−faa+b−a
equals=
2.22.2
9
Equation of tangent line:
10
Expression 11: "t" left parenthesis, "x" , right parenthesis equals "f" prime left parenthesis, "a" , right parenthesis "x" plus left parenthesis, "f" left parenthesis, "a" , right parenthesis minus "f" prime left parenthesis, "a" , right parenthesis "a" , right parenthesistx=f′ax+fa−f′aa
11
Equation of secant line:
12
Expression 13: "s" left parenthesis, "x" , right parenthesis equals left parenthesis, StartFraction, left parenthesis, "f" left parenthesis, "a" plus "b" , right parenthesis minus "f" left parenthesis, "a" , right parenthesis , right parenthesis Over left parenthesis, "a" plus "b" , right parenthesis minus "a" , EndFraction , right parenthesis "x" positive left parenthesis, "f" left parenthesis, "a" , right parenthesis minus StartFraction, left parenthesis, "f" left parenthesis, "a" plus "b" , right parenthesis minus "f" left parenthesis, "a" , right parenthesis , right parenthesis Over left parenthesis, "a" plus "b" , right parenthesis minus "a" , EndFraction "a" , right parenthesissx=fa+b−faa+b−ax+fa−fa+b−faa+b−aa