Hi!

Suppose, we need to compute this integral:

int(sqrt(exp(2*I*t)-1),t) from t=0 to t=Pi

If we write this as definite integral, we get right answer: 2*sqrt(2)-(1/2)*ln(17+12*sqrt(2))

But in case of indefinite integral (computing antiderivative) one gets I*arctan(sqrt(exp(2*I*t)-1))-I*sqrt(exp(2*I*t)-1). Substitution t=Pi and t=0 both lead to 0, so we can't transform antiderivative to definite integral. What is the reason?

I have data file with 6 columns:

X Y Z B1 B2 B3

i.e. 3 coordinates (with some step) and values of B-functions at that 3D point. How to make interpolation of these B-functions to have them in arbitrary (x,y,z) point?

Then I need to solve diff equations like this:

x''(s)+f(...)=0

f(...) depends on x,y,z,x',y',z' and B1,B2,B3. How to write this dsolve(...) construction when we have interpolations inside?

Thanks.