flexx said:thank you mr steve for your interesting in my problem .
still i dont get this :
If later you encounter something like √1+u^2, use 1+(sh(t))^2 = (ch(t))^2 beter than 1+(tg(t))^2 = (sec(t))^2.
you mean that i must substitute by 1+sin²Θ = cos ²Θ ????
There are usually different ways to solve the same problem. For your problem, you can use "variable substitution", which is what you have been trying, or "integration by parts" which is what I wrote in that note. If you prefer "variable substitution", you set u=sh(t) in the integral. It can be integrated very easily. Keep in mind that you can always appeal to the original expression of the hyperbolic functions. For instance, if you encounter (ch(t))^2, you can always replace it by ((exp(t)+exp(-t))/2)^2.flexx said:i dont get what you mean ,
for your solving , i think you use u² , for each substitution we must substitute by
1+cos²Θ ?
This is another way to represent the natural log, which I use "ln", while I use "log" for the base 10 log. Sorry for the confusion.flexx said:and i dont get the ln function in your solveing
2 f (U) = u √1+u2 + ln (u+√1+u²)
what you mean by ln ? we didnt get log yet .
thanking you for your antecipation
I am out of luck helping about that. Or you probably can't. I usually use "Scientific Workplace" to write and then compile as a pdf file.flexx said:but how can you write mathmatics symbols using Acrobat ?