I am sorry but this is all the code I use! s(y) is a piecewise function of degree=3. It results from the Spline function applied to some data points. After defining s(y) I use the following command: int(s,y=-evalf(Pi)..2.338412729); which takes way too long. But if I split the integral in the way: int(s,y=-evalf(Pi)..2); int(s,y=2..2.338412729); 5.060880409 -0.1293817561 I get the results of the integral. How can I upload documents? Thanks for your fast response. Flo

I am sorry but this is all the code I use! s(y) is a piecewise function of degree=3. It results from the Spline function applied to some data points. After defining s(y) I use the following command: int(s,y=-evalf(Pi)..2.338412729); which takes way too long. But if I split the integral in the way: int(s,y=-evalf(Pi)..2); int(s,y=2..2.338412729); 5.060880409 -0.1293817561 I get the results of the integral. How can I upload documents? Thanks for your fast response. Flo

Sorry I forgot to mention that kp is a parameter chosen to kp=4.8486. Now I want the surface area of this function. How can I put a plot in here?

Sorry I forgot to mention that kp is a parameter chosen to kp=4.8486. Now I want the surface area of this function. How can I put a plot in here?