ja da trur det er slik at en blå og en rød samtidig gir komplekst tall og når blå er alene er det reellt tall
Sånn her går det når man må finne ut av ting:
Dear Tor,
Thank you for your feedback regarding Wolfram|Alpha. Take a look at the argument of the logarithm, "x+sqrt(x^2-1)":
http://www.wolframalpha.com/input/?i=x% ... 28x^2-1%29
For x < -1, this function is purely real and negative.
Now let's look at the plot of the logarithm along the real axis:
http://www.wolframalpha.com/input/?i=ln%28x%29
For negative x, the logarithm is complex values with a nonvanishing
real part of size ln(|x|) and a constant imaginary part.
Now let's look at the plot of "plot ln(x+sqrt(x^2-1))":
http://www.wolframalpha.com/input/?i=pl ... ^2-1%29%29
The constant imaginary part and the variable real part follow
from the composition of the above two plots of "x+sqrt(x^2-1)" and ln(x).
Please let us know if you have any other questions.
Best wishes,
Elif
The Wolfram|Alpha Team
www.wolframalpha.com
On Wed Nov 02 16:58:43 2011:
>
>
http://www.wolframalpha.com/input/?i=pl ... t%28x%5E2-
> 1%29%29
> how come the graph is showing blue line for real values for x<-1?
> When x>sqrt(x^2-1) for all x
> ln(x+sqrt(x^2-1)) for x<-1 does not bive answer
> Or am I totally lost here. I have asked someone else as well we just
> can't figure it out. If this means anything else I don't get it.
> Sorry if I am disturbing but I and the one I spoke with could not get
> this and we thought maybe it would be good to ask how this works on
> wolfram.
(fy ikke plag wolfram gill)
