25 = 100 / (1 + 9e^(-2k))
First I multiplied both sides by (1 + 9e^(-2k)) and got
25 + 225e^(-2k) = 100 + 900e^(-2k)
Then I subtracted 225e^(-2k) from 900e^(-2k) and 100 from 25 and got
-75 = 675e^(-2k)
I divided -75 by 675 and got
-1/9 = e^(-2k)
Now I think I'm supposed to take the natural log (ln) of both sides, but when I take the ln of -1/9 my calculator says "error: nonreal answer" What am I doing wrong?
I won't go into the specifics of this question, but I think you can look at what you have and discern what it should look like.
When we graph, we graph the function. For example,
Is the parabola centered at the origin going upwards. If we were to graph this then at specific points we have both an x and a y value (on a graph of the x and y domain).
In the case of your question if we graph in the X and Y domain, all we have is a constant value for Y that doesn't change with respect to X. In fact, it is completely independent of X! Therefore, we should have a straight line at that point.
HOWEVER, if you are graphing Y vs K, then this is not the case. And again we would have a particular point of K/Y but not a line.
See that's kind of important. I didn't know you already subbed in for time! lol
Um...not entirely
Look at your denominator. Where is this min? Well it is min when t=0, why? because the part
Which you can see only gets smaller as time increases. And this is the denominator of our fraction. So smaller denominator --> bigger number
So lets take this to the limit. What happens to our function as t approaches infinity? Well our equation goes to 100. So we have an aysmtote at 100, not at 0.
When t=0 the interscept is 10, not 100.
Are you making sure you put in that negative? It is crucial because that take the e and puts it underneath the 9. Also, your graphing calculator may not like the notation
9e^(-0.55)(X)
It may be thinking that this is equal to
9xe^(-.55)
Try putting both in the bracket like
9e^(-.55x)
Hmm...other then that I don't know because what I wrote is correct.
From your prior posts it looks like you need to review multiplication my man.
Look at
((-272.25e^(0.55t))((e^0.55t) - 9)) / (((e^0.55t) + 9)^3) = 0
If you multiply the left side by the denominator it sure doesn't become
((-272.25e^(0.55t))((e^0.55t) - 9))(((e^0.55t) + 9)^3)
For example, if I have
And I multply both sides by 9, what do I get on the left side?
Yes now to the same for you equations...
((-272.25e^(0.55t))((e^0.55t) - 9)) / (((e^0.55t) + 9)^3) = 0
Multiply the left by our denominator which is
(((e^0.55t) + 9)^3)
and we end up with
((-272.25e^(0.55t))((e^0.55t) - 9))
You said we ended up with
((-272.25e^(0.55t))((e^0.55t) - 9))(((e^0.55t) + 9)^3)
Notice how you multiplied the left side twice!