I'm seeing online that people are saying use the first derivative for this question. did I do this wrong? if so when do I use the first derivative?

a. Use the secant method to find the instantaneous rate of change when x = 1. (4 marks) 6,72- 6- 7.2 rate of y = 201.1 + 3(LD) +1 y = 6.72 1,1 - 1 change 0702) /= 2 (1.018 +3(1. 01)+1 =6.0702 = 7,02 10017 +3(1.001)41 7=6.007002 - 7.002 15 7 b. Use First Principles to find the value of the derivative when