Expressão 7: "m" equals left parenthesis, StartFraction, "f" left parenthesis, "b" , right parenthesis minus "f" left parenthesis, "a" , right parenthesis Over "b" minus "a" , EndFraction , right parenthesism=fb−fab−a
7
What happens if you set "b = a"?
8
This is why we need to take the limit as b approaches a. Otherwise, we would get a slope of 0/0.