mathcad 15 variable undefined

[astevenson-3]

Can anyone please tell me why mathcad 15 chooses to not recognise variable definition when you are using the equation directly under it's definition ie x=x                                                                                                

2*x

[MJG]

You probably need to provide some more information to get a better answer.  However, here are two possible options.

Assign a value to x:

x:=5

2*x=10

Write a function:

f(x):=2*x

f(5)=10

f(7)=14

[Fred_Kohlhepp]

x=x is not a definition.

x := 2   defines the variable x as being equal to the number 2  (shift 🙂

x = x  defines a Boolean constraint (cntrl 😃

[VladimirN]

Just note that after the variable definition, you can change the display of the sign equal (right-click on the definition and select "View Definition As" --> "Colon Equal"/"Equal").