## Replace in a Symbolic Derivative doesnt work with Pi/2

I was writing some small functions for GR applications, and I was defining a Function that gives me the Geodesic equations. When testing if those worked with the Schwarzschild Metric I came upon a problem when trying to replace the angle $$\theta$$ with $$\frac{\pi}{2}$$ this then didn’t properly simplify it when there are derivatives of $$\theta$$.

I have made a simple example to showcase what my problem is:

Sum[D[xx[[i]][\[Tau]], \[Tau]], {i, 4}] /. t -> Pi/2 

This produces the following output:

$$\left(\frac{\pi }{2}\right)'(\tau )+x'(\tau )+y'(\tau )+z'(\tau )$$

What can I do to either prevent this from happening or resolve this issue?

## Gameobject doesn’t move when hits wall

I have a gameobject that moves tile based(It moves 1 unity unit continously when I press button) But when ıt hits a wall, ıt doesn’t move anymore

As you see, When It hits a wall, ıt doesn’t move any direction anymore. Actually I found the problem but I couldn’t find how to solve. The main problem is when cube hits wall, the distance between nextPosition and transform.position never will be <0.0005f But Idk how to solve this.

Those are code that moves cube :

void MovePlayer() {     rb.MovePosition(Vector3.MoveTowards(transform.position, nextPosition, speed * Time.deltaTime));      if (Input.GetKeyDown(KeyCode.W))     {         direction = Vector3.forward;     }      if (Input.GetKeyDown(KeyCode.S))     {         direction = Vector3.back;     }      if (Input.GetKeyDown(KeyCode.A))     {         direction = Vector3.left;     }      if (Input.GetKeyDown(KeyCode.D))     {         direction = Vector3.right;     }      if (Vector3.Distance(transform.position, nextPosition) < 0.0005f)     {         nextPosition = transform.position + direction;     } } 

## Graphics3D doesn’t appear

I think that z values are very closed to each other. So, Graphics3D doesn’t appear.

list={{{-5, -5, 0.126912}, {-5, -4, 0.128462}, {-5, -3, 0.130012}, {-5, -2,     0.131561}, {-5, -1, 0.13311}, {-5, 0, 0.134657}, {-5, 1,     0.136204}, {-5, 2, 0.137748}, {-5, 3, 0.139292}, {-5, 4,     0.140834}, {-5, 5, 0.142373}}, {{-4, -5, 0.162526}, {-4, -4,     0.164015}, {-4, -3, 0.165499}, {-4, -2, 0.166978}, {-4, -1,     0.168451}, {-4, 0, 0.169918}, {-4, 1, 0.171379}, {-4, 2,     0.172833}, {-4, 3, 0.174281}, {-4, 4, 0.175723}, {-4, 5,     0.177157}}, {{-3, -5, 0.195412}, {-3, -4, 0.196719}, {-3, -3,     0.198017}, {-3, -2, 0.199303}, {-3, -1, 0.200579}, {-3, 0,     0.201842}, {-3, 1, 0.203095}, {-3, 2, 0.204335}, {-3, 3,     0.205564}, {-3, 4, 0.20678}, {-3, 5, 0.207984}}, {{-2, -5,     0.222664}, {-2, -4, 0.223665}, {-2, -3, 0.224649}, {-2, -2,     0.225618}, {-2, -1, 0.22657}, {-2, 0, 0.227506}, {-2, 1,     0.228425}, {-2, 2, 0.229327}, {-2, 3, 0.230212}, {-2, 4,     0.23108}, {-2, 5, 0.23193}}, {{-1, -5, 0.241484}, {-1, -4,     0.242067}, {-1, -3, 0.242631}, {-1, -2, 0.243174}, {-1, -1,     0.243698}, {-1, 0, 0.244201}, {-1, 1, 0.244684}, {-1, 2,     0.245147}, {-1, 3, 0.245589}, {-1, 4, 0.24601}, {-1, 5,     0.246411}}, {{0, -5, 0.24973}, {0, -4, 0.249827}, {0, -3,     0.249903}, {0, -2, 0.249957}, {0, -1, 0.249989}, {0, 0, 0.25}, {0,     1, 0.249989}, {0, 2, 0.249957}, {0, 3, 0.249903}, {0, 4,     0.249827}, {0, 5, 0.24973}}, {{1, -5, 0.246411}, {1, -4,     0.24601}, {1, -3, 0.245589}, {1, -2, 0.245147}, {1, -1,     0.244684}, {1, 0, 0.244201}, {1, 1, 0.243698}, {1, 2,     0.243174}, {1, 3, 0.242631}, {1, 4, 0.242067}, {1, 5,     0.241484}}, {{2, -5, 0.23193}, {2, -4, 0.23108}, {2, -3,     0.230212}, {2, -2, 0.229327}, {2, -1, 0.228425}, {2, 0,     0.227506}, {2, 1, 0.22657}, {2, 2, 0.225618}, {2, 3, 0.224649}, {2,     4, 0.223665}, {2, 5, 0.222664}}, {{3, -5, 0.207984}, {3, -4,     0.20678}, {3, -3, 0.205564}, {3, -2, 0.204335}, {3, -1,     0.203095}, {3, 0, 0.201842}, {3, 1, 0.200579}, {3, 2,     0.199303}, {3, 3, 0.198017}, {3, 4, 0.196719}, {3, 5,     0.195412}}, {{4, -5, 0.177157}, {4, -4, 0.175723}, {4, -3,     0.174281}, {4, -2, 0.172833}, {4, -1, 0.171379}, {4, 0,     0.169918}, {4, 1, 0.168451}, {4, 2, 0.166978}, {4, 3,     0.165499}, {4, 4, 0.164015}, {4, 5, 0.162526}}, {{5, -5,     0.142373}, {5, -4, 0.140834}, {5, -3, 0.139292}, {5, -2,     0.137748}, {5, -1, 0.136204}, {5, 0, 0.134657}, {5, 1,     0.13311}, {5, 2, 0.131561}, {5, 3, 0.130012}, {5, 4, 0.128462}, {5,     5, 0.126912}}};     list1 = Flatten[list, 1]; symbols[{x_, y_, z_}] := {Red, Text["\[FivePointedStar]", {x, y, z}]} Graphics3D[Map[symbols, list1]] 

## OptionValue doesn’t work if a local variable has the same name as the function itself

The following innocent-looking code results in error.

Options[add] = {number -> 1}; add[x_, OptionsPattern[]] := Module[{add},    x + OptionValue[number] ]; add[1] 

The error is

# END WordPress

I also have Module rewrite already enabled and

<Directory /var/www/> Options Indexes FollowSymLinks AllowOverride All Require all granted

Still doesn’t work, any ideea?

## WordPress doesn’t send a notification email when submitting a comment using REST API

When I submit a comment on the WordPress website, it sends me a notification email.
but when I submit a comment through REST API, WordPress doesn’t send me a notification email.
What should I do to make WordPress send a notification email when I submit a comment with REST API?