Posted by Aoi on Friday, June 19, 2009 at 9:04am.
given that y=Ae^kx, where A and k are constants, find an expression for dy/dx. Hence find the value of k and of A for which dy/dx  3y = 4e^2x
okay, i know the first part is dy/dx=Ake^kx
but how do i do the second part? find A and k?

Integration?  bobpursley, Friday, June 19, 2009 at 9:17am
if y=Ake^kx then
Ake^kx 3Ae^kx=4e^2x
dividing by e^kx
Ak3A=4(e^(2xkx))
If A,k are constants, then the exponential term has to go to zero (Ak3A) has to equal a constant...
or k=2 to do that, then
2A3A=4 which solves A
Answer This Question
Related Questions
 brief calculus  I found that c=1 but i can't get the other two questions The ...
 maths inequalities...  Find the range of values of k for which the expression x...
 Integration?  Use the derivatives of sinx and cosx to show that d/dx [tanx] = ...
 Math PIZZAZZZ  how does a rodeo star get around?? well if you cant give me an ...
 maths  The first four terms of an arithmetic sequence are 2, xy, 2x+y+7 and x...
 calculus  A quantity has the value P at time t seconds and is decreasing at a ...
 calculus  A quantity has the value P at time t seconds and is decreasing at a ...
 Functions  math  The function f is such that f(x) = 2x + 3 for x ? 0. The ...
 Competetion help on Integration  If there four options are given to a Defenite ...
 calculus  The question I'm having problems with is If f(x)=3x^2+7x+2, find f'(4...
More Related Questions