Question 156348: Trying to find the series for my son's "Chicago Math" 7th grade class. It's an exponetial series with the following (x,y) points (1,1), (2,3), (3,6), (4,10), (nth,?).
Help if you can, Thanks!
Found 2 solutions by stanbon, Earlsdon: Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! exponetial series with the following (x,y) points (1,1), (2,3), (3,6), (4,10), (nth,?
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Exponential Form: y = ab^x
You need to determine a and b.
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Substitute x and y from any two points to get two equaitons:
1 = ab^1
6 = ab^3
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Divide the 1st into the 2nd
6 = b^2
b = sqrt(6)
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Substitute to solve for "a":
1 = a(sqrt(6))^1
a = 1/sqrt(6)
a = 0.408248
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EQUATION:
y = (0.408248)(sqrt(6))^x
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Cheers,
Stan H.
Answer by Earlsdon(6294) (Show Source):
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