If site provides MD5 to check file, can’t the comparison string also not be modified?

I am new to this so please bear with me. I was downloading a VM image and I was told to check the MD5. Naturally, I did but wondered,

If a hacker would change the file to be downloaded from the site, wouldn’t the hacker also be able to change the checksum on the site to make the file look genuine?

If this is the case, wouldn’t this defeat the purpose or is the checksum not really meant for hackers but only problematic downloads over a network?

Can’t find the failure in my jump function

I dont know why but my jump method does not work. My character can only jump on one single object. The other obstacle haven’t any influence on the player. I really don’t see my mistake

     foreach (RectangleShape obstacles in MoveAtObjectList)                {                    MainPlayer.Move(deltaTime, obstacles);                }                 foreach (RectangleShape obstacles in JumpAtObjectList)                {                    MainPlayer.Jump(deltaTime, obstacles);                    break;                }                 Draw();                 Window.Display();            }        }    } } 

This was part of my main Class, where i call the jump method within a foreach loop. Here in my Payer class I tried to write the jump function.

using SFML.Graphics; using SFML.System; using SFML.Window;  namespace Pong3final {     class Player : RectangleShape     {          float CollisionDistance = 0.5f;          float PlayerSpeed = 50;         float JumpSpeed = 100;         float FallSpeed = 100;         float JumpTimer;          bool JumpBool = false;         bool Fall = true;  public  void Jump(float deltaTime, RectangleShape collisionObject)         {              if (Keyboard.IsKeyPressed(Keyboard.Key.Space) && !Fall && CheckCollision(this, collisionObject))             {                 JumpBool = true;             }              //Player is jumping             if (JumpBool)             {                 JumpTimer += deltaTime;                  this.Position -= new Vector2f(0, JumpSpeed) * deltaTime;                  if (JumpTimer > 0.5f)                 {                     JumpBool = false;                     Fall = true;                     JumpTimer = 0;                 }             }              //Player is falling when he doesnt touch anything and he isnt jumping             else if (!CheckCollision(this, collisionObject))             {                 Fall = true;             }              //Player is falling             if (!JumpBool && !CheckCollision(this, collisionObject) && Fall)             {                 this.Position += new Vector2f(0, FallSpeed) * deltaTime;                  if (CheckCollision(this, collisionObject)) //Player stops falling because of a collision with an object                 {                     Fall = false;                 }             }         }           public void Move(float deltaTime, RectangleShape collisionObject)         {             {                 Vector2f MovePlayerPosition = Position;                  if ((Keyboard.IsKeyPressed(Keyboard.Key.Left) || Keyboard.IsKeyPressed(Keyboard.Key.A)))                 {                      MovePlayerPosition -= new Vector2f(PlayerSpeed, 0) * deltaTime;                      FloatRect collisionOverlap;                      if (CheckCollision(this, collisionObject, out collisionOverlap))                     {                        MovePlayerPosition = MovePlayerPosition + new Vector2f(collisionOverlap.Width + CollisionDistance, 0);                     }                     }                  if (Keyboard.IsKeyPressed(Keyboard.Key.Right) || Keyboard.IsKeyPressed(Keyboard.Key.D))                 {                      MovePlayerPosition += new Vector2f(PlayerSpeed, 0) * deltaTime;                      FloatRect collisionOverlap;                      if (CheckCollision(this, collisionObject, out collisionOverlap))                     {                        MovePlayerPosition = MovePlayerPosition - new Vector2f(collisionOverlap.Width + CollisionDistance, 0);                     }                                   }                  Position = MovePlayerPosition;             }         }           public static bool CheckCollision(RectangleShape obj1, RectangleShape obj2, out FloatRect overlap)         {             FloatRect obj1Collider = obj1.GetGlobalBounds();             FloatRect obj2Collider = obj2.GetGlobalBounds();              //Nur die rechte, linke und obere Seite kollidiert             if (obj1Collider.Intersects(obj2Collider, out overlap))             {                 return true;             }             overlap = new FloatRect();             return false;         }          public static bool CheckCollision(RectangleShape obj1, RectangleShape obj2)         {             FloatRect obj1Collider = obj1.GetGlobalBounds();             FloatRect obj2Collider = obj2.GetGlobalBounds();              return obj1Collider.Intersects(obj2Collider);         }     } } 

Why Mathematica can’t return the answer for this integrand?

When I run Integrate command for an expression it doesn’t return nothing, as you can see in the following screenshot. What’s the reason? enter image description here

My input:

Integrate[  1/(2 Sqrt[sp] \[Beta]) E^(-re^2 (se - \[Beta]^2/(4 sp)))    Sqrt[\[Pi]] (-2 +      Erf[(2 (re + rep) sp - re \[Beta])/(2 Sqrt[sp])] +      Erf[(-2 re sp + 2 rep sp + re \[Beta])/(2 Sqrt[sp])] +      Erfc[(2 (re + rep) sp + re \[Beta])/(2 Sqrt[sp])] +      Erfc[(2 rep sp - re (2 sp + \[Beta]))/(2 Sqrt[sp])]), {re,    0, \[Infinity]}] 

DBCA and can’t init database

SQL> startup; ORA-01078: failure in processing system parameters LRM-00109: could not open parameter file '/u01/app/oracle/product/12.2.0.1/db_1/dbs/initAWSDB.ora' 

I created a new Oracle 12c database using dbca

the only files in the dbs directory

$   ls -ltrh total 24K -rw-r--r--. 1 oracle oinstall 3.1K May 15  2015 init.ora -rw-r-----. 1 oracle oinstall   24 Mar 22 23:10 lkCFRDB -rw-r-----. 1 oracle oinstall 3.5K Mar 22 23:13 orapwCFRDB -rw-rw----. 1 oracle oinstall 1.6K Mar 22 23:27 hc_CFRDB.dat -rw-r-----. 1 oracle oinstall 3.5K Mar 22 23:27 spfileCFRDB.ora -rw-rw----. 1 oracle oinstall 1.6K Mar 22 23:42 hc_AWSDB.dat 

When I tried to start up with init.ora

SQL> startup pfile=/u01/app/oracle/product/12.2.0.1/db_1/dbs/init.ora ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated ORA-01262: Stat failed on a file destination directory Linux-x86_64 Error: 2: No such file or directory 

Why can’t the output of the `DiscretizeRegion` function display completely?

mr = DiscretizeRegion[Region[Rectangle[{0, 0}, {Pi, Pi}]],    AccuracyGoal -> 4]   r6 = TransformedRegion[mr,     Function[{t,       p}, {2 Sin[p]^2 Sin[t]^2 + 5 Cos[p]^2 Sin[t]^2 -        Cos[t]^2, (4 Sin[p]^2 Sin[t]^2 +         25 Cos[p]^2 Sin[t]^2 - (2 Sin[p]^2 Sin[t]^2 +           5 Cos[p]^2 Sin[t]^2 - Cos[t]^2)^2 + Cos[t]^2)^0.5`}]]; Region[r6, PlotRange -> {{-1, 5}, {0, 3}}]  DiscretizeRegion[r6, PlotRange -> {{-1, 5}, {0, 3}}] 

Why can’t the output of the DiscretizeRegion function of the above code be displayed completely?

enter image description here

In addition, I don’t know how to change the display size of the uploaded image.

Can’t identify this encryption

jnqLoztC8lrecz-WyBzRjmoblrtzhBuhyrgThPF570s82OnBVNohRgl9eCX61ir9

Composed of 10 numbers, 37 lowercase letters, 16 uppercase letters and 1 hyphen, totaling 64 digits.

No key has been provided.

This topic doesn’t help me at all so don’t bother quoting it.

From my perspective, it could only be a Base64 encryption since it is alphanumeric, however, decrypting it doesn’t lead me anywhere. A Hash function doesn’t look like that either.

I’m out of ideas.