1. M

    Exponential expansion

    I've got a cell line with a gene that gets bigger exponentially. I cultured the cells from 16/1/17 for 295 days and the gene expanded exponentially. For the second culture, cells from culture 1 frozen on 22/5/17 (d127), were thawed on 2/1/18 and cultured for 196 days. For the third culture...
  2. L

    Hi I'm new and have a problem with exponential equation.

    So I'm a Swede and found this site in an attempt to solve a game problem. I have a weapon that do 50 dps and damage more per second to a maximum of 200 dps and it maxes out in 45 seconds. 200 - 50 = 150 150 / 45 = 3,33... So it does 3,33 extra damage per second. Now i want to know how...
  3. O

    Modelling tetrahedral numbers

    Hi, I hope someone can help. I'm trying to solve for a): I developed the equation y = 4^x, where "x" represents an additional 4 sides. This equation works perfectly well, however, it is different from the textbook's solution. The textbook's solution is the following: Can someone please...
  4. O

    Exponential function word problem

    Hi, I hope someone can help. My textbook has been extraordinarily incorrect with its solutions in the past, so I want to make sure with the following questions that my textbook is wrong in this case and not the other way around. As follows: Can someone please let me know what solution they...
  5. O

    Graphing exponential functions

    Hi, I hope someone can help. I'm trying to calculate what the instantaneous rate of change would be at year 2 for the following table: I'm suppose to plot these points on a graphing calculator and then find the values of y (students per computer) that are close to year 2, then use these...
  6. O

    Exponential equation word problems

    Hi, I hope someone can help. I'm trying to solve the following question: As stated above, the equation is N(t) = 3^(t+1). N(t) represents the number of people told during the hour t, and t = 1. However, let's say that we wanted to develop an equation which fit the same context that...
  7. C

    Help with exponential generating function proof

    Use exponential generating functions to prove that: P(n) = P(n-1) + n, with n >= 1 and P(0) = 1 will result in this equation: P(n) = (1/2)n2 + (1/2)n + 1 I know how to do this with generating functions, you just plug in n=1, n=2, n=3,.... P(1) will result in (1/2)(1)2 + (1/2)(1) +1 which is 2...
  8. C

    Exponential generating functions help understanding

    Use exponential generating functions to prove that: P(n) = P(n-1) + n, with n >= 1 and P(0) = 1 will result in this equation: P(n) = (1/2)n2 + (1/2)n + 1 I know how to do this with generating functions, you just plug in n=1, n=2, n=3,.... P(1) will result in (1/2)(1)2 + (1/2)(1) +1 which is 2...
  9. V

    Exponential Functions and Equations - Practice Test

    hellooo, i'm having some trouble completing an exponential functions practice test, please help!!! please don't use logarithms as i haven't learnt about them and the unit does not cover them. i am attaching a pdf file below, the practice test is on the last two pages! it would be great if you...
  10. J

    Implicit Differentiation

    y^2 = e^(xy) y' = ye^(xy) / [ 2y - xe^(xy) ] Is it wrong if my final answer written Like this? y = sqrt[ e^(xy) ] y' = ( sqrt[ e^(xy) ] )e^(xy) / [ 2( sqrt[ e^(xy) ] ) - xe^(xy) ]
  11. J

    Limit of Infinity for Exponential Absolute Function

    Find the indicated limit. lim as x goes infinity of |(x + 1) / (x - 2)|^(x^2 - 4)^(1/2)
  12. B

    Solve for x in an exponential equation

    I found this equation in the grade above's (year 12) textbook, and I've been trying for a day to solve it with full working out. e^(2x)-e^(x)-2=0 I'm just not sure what working out I need to do. If anybody could post the answer with full working out, it'd be much appreciated.
  13. C

    Exponential Models and Applications

    Can someone please help me with this problem: The population (in millions), p and q, of two neighbouring American states, P and Q, over a period of 50 years from 1950 are modelled by functions p = 1.2 x 2^0.08t and q = 1.7 x 2^0.04t. Find when the population of state P is: a) equal to the...
  14. C

    Exponential Models and Applications

    Hi everyone, so I'm doing some worded questions but they are hard for me to understand. The half-life of plutonium-239 is 24,000 years. If 10 grams are present now, how long will it take until only 10% of the original sample remains (give your answer to the nearest year). Some worked examples...
  15. A

    exponential to logarithm

    Hi; I need to convert f(x) = 2(3/4)^((x+3)/2) - 8 to logarithmic form. y + 8 = 2(3/4)^((x+3/2) y/2 + 4 = (3/4)^((x+3)/2) log(y/2 + 4) = ((x+3)/2)log(3/4) not sure where to go from here or is it all wrong? Thanks.
  16. A

    convert transformed log to exponential

    Hi; Trying to convert y = -2log(base3/4)(1/2x + 4) -3 to exponential form. what I did switch x and y: x = -2log(base3/4)(1/2y + 4) - 3 add 3 to both sides: x + 3 = -2log(base3/4)(1/2y + 4) divide both side by -2: (x + 3)/-2 =...
  17. M

    Exponential Growth and Decay Problem.

    At the start of an experiment, 2 x 10^4 bacteria are present in a colony. Eight hours later, the population is 3 x 10^4. (a) determine the growth constant k. (b) what was the population two hours after the start of the experiment? Formula for this: N=N_o(e)^(kt) N= is the sum of answer...
  18. U

    Numerov method on a exponential grid mesh

    Hi there. I was trying to implement Numerov method for solving second order differential equations (you can see some information of Numerov algorithm at here: https://en.wikipedia.org/wiki/Numerov%27s_method ). At the beginning I've used a uniform grid mesh, all points equally spaced. I'm...
  19. A

    Gamma and exponential distribution

    I think I'm about to lose my mind. I'm relearning gamma and exponential distribution. I know that exponential distribution is a special case of gamma, that is when alpha is equal to 1. Also I know that exponential distribution deals with measuring the waiting time until a random event happens...
  20. G

    exponential equation problem ~~

    Hi So my question is asking me to solve for x in the formula t=-5\log{\frac{5-x}{5}} my final answer came out to be x= (^5\sqrt{3125 -\frac{3125}{10^t}}) i have attached my work to see how i got there but i feel as i did something wrong any help would be great thanks.