SOLUTION: Hi, I hope you please can help me with this one; I have found this equation from a graph I created: y = 50,88e^-0,01x I already know that y = 50, so I have to find the x. I kn

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Hi, I hope you please can help me with this one; I have found this equation from a graph I created: y = 50,88e^-0,01x I already know that y = 50, so I have to find the x. I kn      Log On


   



Question 119762: Hi, I hope you please can help me with this one;
I have found this equation from a graph I created: y = 50,88e^-0,01x
I already know that y = 50, so I have to find the x. I know I have to divide/multiply with ln or something like that, but I can't come any further on my own.
I would really appriciate your help!

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
I have found this equation from a graph I created:
y = 50.88e^-0,01x
I already know that y = 50, so I have to find the x.
:
50.88e^-0.01x = 50
:
Divide both sides by 50.88
e^-0.01x = 50%2F50.88
:
Using nat logs;
ln(e^-0.01x) = ln(50%2F50.88)
:
Write the log equiv of exponents
-.01x*n(e^) = ln(50%2F50.88)
:
Find the ln of both sides (we know ln of e = 1), so we have:
-.01x = -.0174469
:
x = %28-.0174469%29%2F%28-.01%29
:
x = +1.74469
:
:
Check solution on a good calc: enter 50.88(e^(-.01*1.74469)) = 50
:
Did this help?