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Revolve a function along the x-axis in Wolfram|Alpha?

The following command in W|A returns invalid limits: 

revolve f(x)=a/2(e^(x/a) + e^(-x/a)), x = 1 to b, around the x-axis

How can I solve this problem?
POSTED BY: Rosa María Diaz Palacios
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Hi Maco, Thank you very much for giving solution to my problem. It was quite quick to respond
POSTED BY: Rosa María Diaz Palacios

Dear Rosa,

where to you enter that? Wolfram|Alpha? Mathematica.

I guess that it says that the limits are invalid, because the upper limit of x is b and that is for a plot, which involves numerical evaluation, invalid.

I would suggest you use in Mathematica

RevolutionPlot3D[a/2 (Exp[x/a] + Exp[-x/a]) /. a -> 2, {x, 1, 5}]

enter image description here

If you don't have Mathematica you can use the free account of the development platform or the programming lab. I guess that the Raspberry Pi version can do that, too. Note that I "corrected" the Exp function and substituted values for a and b.

Wolfram|Alpha will not interpret that syntax correctly though.

Cheers,

Marco
POSTED BY: Marco Thiel
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