Exponential relationships to logarithms and straight line graph?

Click For Summary
SUMMARY

The discussion focuses on the exponential growth of cell division modeled by the equation y = 64 x 2^(2t). To analyze this relationship, participants suggest using logarithms to convert the exponential equation into a linear form. By taking the logarithm of both sides, the equation transforms into Y = 2t + 6, where Y = log2(y). The graph crosses the Y-axis at (0, 6) and the T-axis at (3, 0), confirming the linear relationship derived from the logarithmic transformation.

PREREQUISITES
  • Understanding of exponential functions and their properties
  • Knowledge of logarithmic functions and their applications
  • Familiarity with graphing linear equations
  • Basic algebra skills for manipulating equations
NEXT STEPS
  • Study the properties of logarithms, specifically log2(x)
  • Practice converting exponential equations to linear forms using logarithms
  • Learn how to graph linear equations and identify intercepts
  • Explore applications of exponential growth in biological contexts
USEFUL FOR

Students studying mathematics, particularly those focusing on algebra and logarithmic functions, as well as biologists interested in modeling cell growth patterns.

JakePearson
Messages
52
Reaction score
0
it is suspected that cells in a sample are dividing so that the number of cells present at anyone time t (measured in seconds) is growing exponentially according to the relationship y = 64 x 2^2t. it would be hard to check this relationship accurately by plotting measurements of y against t, so in practice one can use logarithms to convert it to a linear line equation. sketch a graph of log(base2)y against t, labelling the point where the graph crosses the axes?
how to i find the points on x and y-axis where the line crosses, i believe the line will be a straight line, how do i do this?

I REALLY HAVE TRIED WITH THIS QUESTION, IT HAS TAKEN ME THE WHOLE DAY TO TRY AND DO, I HOPE SOMEONE CAN SHOW ME HOW TO DO THIS :)
 
Physics news on Phys.org
What, exactly, did you spend all day doing? Taking the logarithm of both sides of [itex]y= 64(2^{2t})[/itex] gives [itex]ln(y)= log(64)+ 2t log(2)[/itex]

That is of the form Y= at+ b where Y= log(y), a= 2log(2), and b= log(64). It crosses the Y axis when t= 0, at (0, ln(64)) and the t axis when Y= 0, at t= log(64)/(2log(2)).

I specifically did not give a base for the logarithm because the above is true for any base. It is particularly simple if you use, not "common" or "natural" logarithm, but the logarithm base 2: [itex]log_2(2)= 1[/itex] and [itex]log_2(64)= log_2(2^6)= 6[/itex] so Letting [itex]Y= log_2(y)[/itex], the equation becomes Y= 2t+ 6 with intercepts at (0, 6) and (3, 0).
 
cheers mate, i wasnt doing that, i think i need to spend more time and concentration on logs and try a number of different questions on it, thanks again
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
2
Views
2K
Replies
3
Views
2K
Replies
14
Views
3K
  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 10 ·
Replies
10
Views
6K