## 128 Reputation

13 years, 360 days

## inconsisten numerical answers between ev...

Maple
Hello, I have this complicated and messy (complex) function, called ratio, of a variable f0. (Sorry the function is really long). 1) suppose I set f0 = 5.0e9, then evalf(ratio) gives 0.3832106695. 2) if I were to plot ratio via, with(plots): plotr := semilogplot(ratio,f0=5e9..1e12,color=black,numpoints=1000,axis = [tickmarks=[4,subticks=8]],axis = [tickmarks=[4,subticks=5]], view=[1.0e9..1.0e12,0.40..1.00]): display(plotr); then on the plot it shows that ratio > 0.40 at f0 = 5.0e9. Could anyone help please? Thanks! The function is listed below, ratio := 0

## problem with y-axis labels in logplot...

Maple
Hello, I ran into some problems with the y-axis labeling and tickmarks, and would appreciate any help you could offer. Thanks! The y-axis plotted below has two 10^(-6) labels, and the tickmarks on the y-axis do not look correct either (more than 10 subtickmarks per order of magnitude!). -Dan > restart; >with(plots); > dBv := 37.43; dBv := 31.29; dBv := 25.75; dBv := 20.86; dBv := 16.54; dBv := 12.58; dBv := 9.28; dBv := 6.02; dBv := 3.32; dBv := 1.25; dBv := -1.54; dBv := -3.38; dBv := -5.45; dBv := -7.2; dBv := -8.04; dBv := -8.29; dBv := -10.06; dBv := -9.32; dBv := -10.53; dBv := -9.71;

## choosing tickmarks in logplot...

Maple
Hello everyone, I have a problem with Maple 11's choice of tickmark spacing in a logplot, >pdata := logplot(points, style=point, symbol=circle, thickness=2, color=red): The resulting plot has the y-axis tickmarks located only at [1 x 10^n, 5 x 10^n, 1 x 10^(n+1), 5 x 10^(n+1), ...] How do I make Maple show the more conventional log-scale tickmarks at [1 x 10^n, 2 x 10^n, 3 x 10^n, ..., 1 x 10^(n+1), 2 x 10^(n+1), ...] Thanks much for your help! -Dan

## how do I really unassume a variable in M...

Maple
Hello everyone, thanks for your help in advance! To perform the integral of this function over rho: >f1 := alpha*(3*lambda^3*rho*d/(rho^2 + d^2)^(5/2)); I need to assume the variable (d > 0): so, >assume(d > 0); >I1 := int(f1,rho=a..b); >I1; 3 2 2 (3/2) 2 2 (3/2) alpha lambda d~ (-(b + d~ ) + (a + d~ ) ) - ----------------------------------------------------- 2 2 3/2 2 2 3/2 (a + d~ ) (b + d~ ) but I cannot now plug in real numbers for d in I1 (e.q. d := 3.0). I get the same I1 expression as above, with d~. I tried unassume(d > 0), but it did not help. Anyway, thanks for your help.

## help with numerical answer to maple expr...

Maple
Hello, I have the following maple expression (sorry, it is somewhat lengthy)

e_x0 :=

4*ep^2*sin(m*Pi/b*y)*sin(n*Pi/c*z)*J0*(x1-x0)*(-cos(n*Pi/c*z1)+cos(n*Pi/c*z0))*(-cos(m*Pi/b*y1)+cos(m*Pi/b*

y0))/((2*m^2*Pi^4*c^2*n^2*b^2+n^4*Pi^4*b^4+8*Pi^4*m^4*c^4*Q^2+16*Pi^4*m^4*c^4*Q^4+16*k^4*b^4*c^4*Q^4+8*m^2*

Pi^2*c^4*k^2*b^2*Q^2-32*Pi^2*n^2*b^4*Q^4*k^2*c^2+8*n^2*Pi^2*b^4*k^2*c^2*Q^2+m^4*Pi^4*c^4-32*Pi^2*m^2*c^4*Q^

4*k^2*b^2+16*Pi^4*m^2*c^2*Q^2*n^2*b^2+8*Pi^4*n^4*b^4*Q^2+32*Pi^4*m^2*c^2*Q^4*n^2*b^2+16*Pi^4*n^4*b^4*Q^4)/b

^4/c^4/Q^4)^(1/2)/a/m/Pi^2/n;

and the input parameters are
 Page 1 of 1
﻿