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OT: Converting y = Ae^bx to base 10 - How does Excel calculate b ???

Posted By: leobueno
Date: Monday, 30 January 2012, at 1:44 p.m.

In Response To: OT: Converting y = Ae^bx to base 10 - How does Excel calculate b ??? (Sam Pottle)

Sam said: "c isn't 0.1, 10^c is 1.1."

I am trying to go from the Excel b exponent to the growth rate, call it g, which in the example equaled 10% (where Excel's b was 0.09531).

So now I need to find the relationship between c and g (so I can get the conversion from b the Excel exponent to g the growth rate).

If 10^c = 1.1 then letting g be the growth rate, does this follow?

10^c = 1.1 = 1+g

cLOG(10) = LOG(1+g) (where LOG is the base 10 log)

c = LOG(1+g) = bLOG(e)

1+g = 10^bLOG(e)

g = [10^bLOG(e)]-1 (where LOG(e) is a constant, roughly 0.4343)

Messages In This Thread

• OT: Converting y = Ae^bx to base 10
  leobueno -- Sunday, 29 January 2012, at 3:12 p.m.
  • OT: Converting y = Ae^bx to base 10
    Casper van der Tak -- Sunday, 29 January 2012, at 3:22 p.m.
    • OT: Converting y = Ae^bx to base 10
      Jason Lee -- Sunday, 29 January 2012, at 3:48 p.m.
      • OT: Converting y = Ae^bx to base 10 - How does Excel calculate b ???
        leobueno -- Sunday, 29 January 2012, at 7:20 p.m.
        • OT: Converting y = Ae^bx to base 10 - How does Excel calculate b ???
          Sam Pottle -- Sunday, 29 January 2012, at 9:14 p.m.
          • OT: Converting y = Ae^bx to base 10 - How does Excel calculate b ???
            Jake Jacobs -- Monday, 30 January 2012, at 2:38 a.m.
            • OT: Converting y = Ae^bx to base 10 - How does Excel calculate b ???
              Michael Petch -- Monday, 30 January 2012, at 3:56 a.m.
          • OT: Converting y = Ae^bx to base 10 - How does Excel calculate b ???
            leobueno -- Monday, 30 January 2012, at 1:44 p.m.
            • OT: Converting y = Ae^bx to base 10 - How does Excel calculate b ???
              Sam Pottle -- Monday, 30 January 2012, at 3:43 p.m.