A patient's pulse measures 110 bpm, 70 bpm, then 60 bpm. To determine an accurate measurement of pulse, the doctor wants to know what value minimizes the expression

Question

(x − 110)2 + (x − 70)2 + (x − 60)2.
What value (in bpm) minimizes it?

Answer 1

C=(x − 110)2 + (x − 70)2 + (x − 60)2.
dC/x=2(x-110)+2(x-70) + 2(x-60)=0
6x=220+140+120
x=480/6 = ...