# Math Help - exponential function

1. ## exponential function

Evolution of Language: The number of years, n, since two independently evolving languages split off from a common ancestral language is approximated by

n=-7600 log r,

where r is the proportion of words from the ancestral language common to both langages.

(a) Find n if r=.9. (b) Find n if r=.3

(c) How many years have elasped since the spilt if half of the words of the ancestral language are common to both languages?

2. Originally Posted by norwoodjay
Evolution of Language: The number of years, n, since two independently evolving languages split off from a common ancestral language is approximated by

n=-7600 log r,

where r is the proportion of words from the ancestral language common to both langages.

(a) Find n if r=.9. Chris says substitute r=.9 into the equation and evaluate $-7600\log(.9)$

(b) Find n if r=.3 Chris says substitute r=.3 into the equation and evaluate $-7600\log(.3)$

(c) How many years have elasped since the spilt if half of the words of the ancestral language are common to both languages? Chris says that r is given to us: r=.5. Now evaluate $-7600\log(.5)$
Does this make sense?

--Chris

3. Chris can you give me the final solution answer?