MathsHelpPlz
New member
- Joined
- Dec 13, 2012
- Messages
- 23
Not sure where this question belongs, but:
"N represents the number of cells at a time 't' minutes after the start of the growth, and the relationship between 'N' and 't' was thought to be modelled by N=a(b^t), where 'a' and 'b' are constants. Find the values of a and b to the nearest integer"
I correctly found 'b' to be 2.
I drew a graph of Log2(N) against 't' and found the y-intercept to be 3.17, so, using Log2(N)=Log2(a) + tLog(b) I equated Log2(a)=3.17 and found 'a' as 2^3.17 ~ 9. However if I used the different method of letting 9=a(b^1.5) where b was found to be (19/9)^(1/2) via 19=9(b^1.2), I got 'a' as 9/(b^1.5) which is 3.53674416 ~ 4.
I was wondering how come I get different results with the different methods?
Thank you for your time.
"N represents the number of cells at a time 't' minutes after the start of the growth, and the relationship between 'N' and 't' was thought to be modelled by N=a(b^t), where 'a' and 'b' are constants. Find the values of a and b to the nearest integer"
t | 1.5 | 2.7 | 3.4 | 8.1 | 10 |
N | 9 | 19 | 32 | 820 | 3100 |
I correctly found 'b' to be 2.
I drew a graph of Log2(N) against 't' and found the y-intercept to be 3.17, so, using Log2(N)=Log2(a) + tLog(b) I equated Log2(a)=3.17 and found 'a' as 2^3.17 ~ 9. However if I used the different method of letting 9=a(b^1.5) where b was found to be (19/9)^(1/2) via 19=9(b^1.2), I got 'a' as 9/(b^1.5) which is 3.53674416 ~ 4.
t | 0 | 1.2 | 1.9 | 6.6 | 8.5 |
Log2(N) | 3.17... | 4.25... | 5.00 | 9.68... | 11.60... |
I was wondering how come I get different results with the different methods?
Thank you for your time.
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