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# Why this Integral is not working?

Posted 9 years ago
 I am trying to integrate a function but mathematica is returning the integral without solving 8 Replies
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Posted 9 years ago
 Thanks a lot Gianluca Gorni . I was looking for some analytic results. But it seems there is none for this Integral.
Posted 9 years ago
 It seems that the spaces between the letters bax went lost in the text. Write b a x with explicit spaces.
Posted 9 years ago
 Why I am getting the following errors while using your code for numerical Integration? NIntegrate::inumr: The integrand x/Sqrt[(0.990099 (1+bax^2)-x^2) (1-0.1 x^2.)] has evaluated to non-numerical values for all sampling points in the region with boundaries {{0,1}}. >>
Posted 9 years ago
 In Mathematica syntax the curly braces {} are for lists. To indicate the order of algebraic operations you should use parentheses () instead. In general your integral seems too difficult to calculate symbolically: With[{a = 1/2, b = 1, d = 3}, f[x_] := 1 - a*x^d; k[x_] := 1 + b*a*x^d; h[x_] := x^(d - 1)/Sqrt[f[x]*((k[x]/k) - x^(2*d - 2))]; Integrate[Simplify@h[x], {x, 0, 1}]] However you can calculate it numerically: Manipulate[ f[x_] := 1 - a*x^d; k[x_] := 1 + b*a*x^d; h[x_] := x^(d - 1)/Sqrt[f[x]*((k[x]/k) - x^(2*d - 2))]; NIntegrate[h[x], {x, 0, 1}], {a, 0, 1}, {b, 0, 2}, {d, 2, 4}] You can also plot the function:Manipulate[ f[x_] := 1 - a*x^d; k[x] := 1 + bax^d; h[x] := x^(d - 1)/Sqrt[f[x]((k[x]/k) - x^(2d - 2))]; Plot[h[x], {x, 0, 1}], {a, 0, 1}, {b, 0, 2}, {d, 2, 4}]
Posted 9 years ago
 I have modified my integral a bit. But it is again not working.I have also tried to plot the function but it is showing an error. enter code here f[x_] := 1 - {a*x^d} k[x_] := 1 + {b*a*{x^d}} h[x_] := x^{d - 1}/Sqrt[f[x]*{{k[x]/k} - x^{2*d - 2}}] Integrate[h[x], {x, 0, 1}, Assumptions -> {x > 0, 0 < a < 1, b > 0, d > 2}] it is giving the following error {{{{Integrate[x^(-1+d)/Sqrt[(1-a x^d) (-x^(-2+2 d)+(1+a b x^d)/(1+a b))],{x,0,1},Assumptions->{x>0,00,d>2}]}}}}
Posted 9 years ago
 I would also remove the curly braces around a*x^d: f[x_] := 1 - a x^d; h[x_] := Sqrt[f[x]]; Integrate[h[x], {x, 0, 1}, Assumptions -> {a > 0, d > 1}] 
Posted 9 years ago
 Thanks a lot .I have just started using mathematica. So It will take sometime to get used to with the notation.
Posted 9 years ago
 Capitalize sqrt