G gtpeebs New member Joined Dec 6, 2011 Messages 2 Dec 6, 2011 #1 Definite Integral Help ∫[-1,2]x√3:(x^2-5)*dx We are doing integrals in school and I cannot figure out how to do these. Can someone show me an example on this? ∫[-1,2]x√3: (x^2-5)*dx Thanks Last edited: Dec 7, 2011
Definite Integral Help ∫[-1,2]x√3:(x^2-5)*dx We are doing integrals in school and I cannot figure out how to do these. Can someone show me an example on this? ∫[-1,2]x√3: (x^2-5)*dx Thanks
tkhunny Moderator Staff member Joined Apr 12, 2005 Messages 11,325 Dec 6, 2011 #2 Is it this? \(\displaystyle \int_{-1}^{2}\frac{x\sqrt{3}}{x^{2}+5}\;dx\)? If so, try a substitution. u = x^2 + 5 looks compelling.
Is it this? \(\displaystyle \int_{-1}^{2}\frac{x\sqrt{3}}{x^{2}+5}\;dx\)? If so, try a substitution. u = x^2 + 5 looks compelling.
G gtpeebs New member Joined Dec 6, 2011 Messages 2 Dec 7, 2011 #3 Its actually the 3rd root of (x^2-5) so it should be the following, x 3rd SqRt (x^2-5) at -1, 2 Last edited: Dec 7, 2011
tkhunny Moderator Staff member Joined Apr 12, 2005 Messages 11,325 Dec 7, 2011 #4 Oh, well, in that case, u = x^2 - 5 looks like a compelling substitution. Please show us ANY work.
