Guest pook Posted June 23, 2004 Share Posted June 23, 2004 Can someone quickly tell me what the integral of 1 over e^y(x) is I have a seperable DE im trying to solve. Pook (: Link to comment Share on other sites More sharing options...
Dave Posted June 23, 2004 Share Posted June 23, 2004 There is no general form for that integral. If you specify a function for y(x) I might be able to help. Link to comment Share on other sites More sharing options...
MandrakeRoot Posted June 24, 2004 Share Posted June 24, 2004 If you would pose y(x) = x^2 it is even known that there is no analytic expression (in terms of standard functions) for the integral, other than int_0^x exp(z^2) dz ofcourse. Mandrake Link to comment Share on other sites More sharing options...
Guest smithe Posted October 26, 2004 Share Posted October 26, 2004 Im struggling with the intergration of 'e' aswell! 70e^(-0.1t) Have no idea, can anyone help! Link to comment Share on other sites More sharing options...
WaR Posted October 26, 2004 Share Posted October 26, 2004 If you mean that the function is with respect to t (obviously ) then just make it a u substitution. In detail: Let u = -0.1t Then, du/-0.1=dt Now solve for (integral)70e^u du Link to comment Share on other sites More sharing options...
bloodhound Posted October 26, 2004 Share Posted October 26, 2004 in general [math]\int{ae^{bx}}dx=\frac{a}{b}e^{bx}+k[/math] Link to comment Share on other sites More sharing options...
Dave Posted October 27, 2004 Share Posted October 27, 2004 The other way to look at it to "guess" which function differentiates to give the function you're integrating. i.e. guess [math]\tfrac{1}{a} e^{ax}[/math]. Then if you differentiate this, you get your integral, so that's your answer. Link to comment Share on other sites More sharing options...
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