# Math Help - need help

1. ## need help

Table 1.9 shows some values of a linear function f and an exponential function g. Find exact values (not decimal approximations) for each of the missing entries of f, and round your answers for g to 3 decimals.

Table1.9 x 0 1 2 3 4

f(x) 15 30
g(x) 15 30

mathlete

2. Originally Posted by mathlete
Table 1.9 shows some values of a linear function f and an exponential function g. Find exact values (not decimal approximations) for each of the missing entries of f, and round your answers for g to 3 decimals.

Code:
Table1.9 x 0  1  2   3   4

f(x)         15     30
g(x)         15     30

mathlete

$f(x)=mx+c$

determine $m$ and $c$ from the given data, and then fill in the missing values.

$g(x)=A e^{kx}$

determine $A$ and $k$ from the given data, and then fill in the missing values. This may be simplified by taking logs when you have:

$\ln(g(x))=k \ln(x) + \ln(A)$

RonL

As I said there, you don't need to find the equations.

f(2)-f(1)=f(1)-f(0)

g(2)/g(1)=g(1)/g(0)

4. Originally Posted by a tutor

As I said there, you don't need to find the equations.

f(2)-f(1)=f(1)-f(0)

g(2)/g(1)=g(1)/g(0)

Indeed you don't, but this won't work as it is either since the functional values at 1 and 3 are given not 0 and 2;
or are they - difficult to tell from the original question

RonL

5. Originally Posted by CaptainBlack
Indeed you don't, but this won't work as it is either since the functional values at 1 and 3 are given not 0 and 2;
or are they - difficult to tell from the original question

RonL
On quoting it seems they are at 0 and 2, Captain.

6. Originally Posted by CaptainBlack
the functional values at 1 and 3 are given not 0 and 2;
or are they - difficult to tell from the original question
It is hard to tell. I took them to be values for x=0 and x=1.

In any case you can just use $\sqrt{\frac{g(3)}{g(1)}}$ if the values were x=1 and x=3.