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Question: What's wrong with my "asympt"?

Question:What's wrong with my "asympt"?

Luna Moon 353 Maple
complex input infinity
August 02 2007
0
What's wrong with my "asympt"? Hi all, I want to find out the order of growth/decay of expression CCP1(attached below). CCP1 is a sub-expression of my huge expression(which Maple couldn't handle). The goal is to find the functional form for my expression as "v" and "t" approaches +infinity, so that I can bound the error after truncating it, because I am using this as an integrand. The original huge expression is known to be fast decay in "v" -- I suspect the asympotic order is of exp(-a*v)/(v+b)^n. But this sub-expression might be decay, it may grow at +infinity. The goal is to find out the asymptotic order of growth/decay so that when I combine with the results from other expressions I can get the overall decay order. All the original parameters/variables [a, xbar, sigma2, eps, c, g, v] are real and positive. The intermediate variables "gamma" and "u" are complex-valued(they were substituted by other expressions). As you can see, I got an error. What's wrong? Please help me! Thanks a lot! ----------------------- gamma:=0.5*sqrt(a^2+2*u*sigma2); CCP1 := (gamma*exp(.5*a*t)/(gamma*cosh(gamma*t)+.5*a*sinh(gamma*t)))^(2*a*xbar/sigma2); print(`output redirected...`); # input placeholder // (1/2) \// (1/2) / || / 2 \ | | / 2 \ | \\0.5 \a + 2 u sigma2/ exp(0.5 a t)/ \0.5 \a + 2 u sigma2/ cosh\0.5 (1/2) \ / (1/2) \\\ / / 2 \ | | / 2 \ |||^| \a + 2 u sigma2/ t/ + 0.5 a sinh\0.5 \a + 2 u sigma2/ t/// \ 2 a xbar\ --------| sigma2 / with(MultiSeries, asympt); `assuming`([asympt(subs(u = c+g*(-eps+I*v), CCP1), v)], [positive]); %; [asympt] Error, (in assuming) when calling 'MultiSeries:-multiseries'. Received: 'unable to sort exponents, {-.5000000000*t~*Re(((2.*I)*g~*sigma2~)^(1/2)), .5000000000*t~*Re(((2.*I)*g~*sigma2~)^(1/2))}, MultiSeries:-multiseries'
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