## 120 Reputation

11 years, 188 days

## Evaluate a sum with a vector input ...

Maple

Experts,

I have a series as follows:

b := (sum((x[i]-xbar)^3, i = 1 .. n))/(n*[(sum((x[i]-xbar)^2, i = 1 .. n))/(n-1)]^1.5)

(b is skewness of x)

Taking the derivatives:

c1:=diff(b, xbar);

c2:=diff(b, x[i]);

now I want to evaluate c1 and c2 with a matrix input:

x:=<<0.556960605000000>,<3.39039994000000>,<2.09005200300000>,<0.645104568000000>,<5.31340491600000>,<3.32743462200000>,<0.635452131000000>,<1.56878297000000>,<0.282764039000000>,<1.02862059900000>,<3.14927606700000>,<0.654644768000000>,<1.30502450500000>,<2.13887537900000>,<2.11803658900000>,<7.29488570500000>,<0.478693554000000>>

where xbar is the mean value of x

Thanks

## Highlighting the intersection of two sur...

Maple 18

I want to highlight the intersection between 2 graphs; pp(m,a) and the plane m=-0.2

PP := .8707945038*exp(-50.00000000*(m-0.842e-1)^2+(2.745342070*(m-0.842e-1))*(a-2.3722)-.1046792095*(a-2.3722)^2)

How can I do that?

Thank you

## integral of erfc(x)...

Maple 18

I am trying to calculate the integral

where

Maple cannot calculate the integral. I tried to expand theta in the series form and substitute in the integral, still cannot calculate it.

any suggestion to tackle this problem whould be helpful.

Thank you

## Wierd digits on my Graphs!!! ...

Maple 18

Friends

I have plotted some figures and saved them yesterfay!

now once i opened them some nonsence digits appear on the figure! see the picture please. anyone has similar experience? how to solve it!

Dont make me disappointed maple! two days work is invain now !

## Contour plots in a 3d graph...

Maple

Hi all,

I have a 3D graph and when I right click on the surface, under style, I can see the option of contour. When I click on that I can see some contour associated with the surface. I want maple to show the values for each contour when I observe it from the top . I want to copy and paste some surfaces in a same figure and campare the contours.

Thank you

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