# Question:figure draw problem why unable to evaluate the function to numeric values in the region pls explain

## Question:figure draw problem why unable to evaluate the function to numeric values in the region pls explain

Maple

> restart;
> u := c-6*mu*(1+lambda*sqrt(-mu)*coth(A+sqrt(-mu)*(x+y+mu*t)))/((a+b)*sqrt(-mu)*coth(A+sqrt(-mu)*(x+y+mu*t)))+6*mu*sqrt(sigma*(1-coth(A+sqrt(-mu)*(x+y+mu*t))^2))/(sqrt(sigma)*(a+b)*sqrt(-mu)*coth(A+sqrt(-mu)*(x+y+mu*t)));
/                (1/2)     /         (1/2)               \\
6 mu \1 + lambda (-mu)      coth\A + (-mu)      (x + y + mu t)//
c - ----------------------------------------------------------------
(1/2)     /         (1/2)               \
(a + b) (-mu)      coth\A + (-mu)      (x + y + mu t)/

(1/2)
/      /                                       2\\
|      |        /         (1/2)               \ ||
6 mu \sigma \1 - coth\A + (-mu)      (x + y + mu t)/ //
+ -----------------------------------------------------------------
(1/2)              (1/2)     /         (1/2)               \
sigma      (a + b) (-mu)      coth\A + (-mu)      (x + y + mu t)/
> c := 1;
1
> mu := -1.5;
1.5
> lambda := 1.5;
1.5
> a := 1;
1
> b := 1;
1
> A := .5;
0.5
> y := 0;
0
> plot3d([abs(u)], x = -10 .. 3, t = -10 .. 3);
Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct

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