Error in if funtion

[MM_10735997]

how can i correct this error in the function

[Cornel · Accepted solution]

[Werner_E]

Some remarks:

• The function "and" is only for matrix arguments look it up in the help. You have to use the "and operator" ^ as Cornel had shown
• There is a unit mismatch! You can only calculate f-l if both are of the same dimension. So either both must be unit-less (like f is) or both must be lengths (like l is). Choose d:=20m in Cornels sheet to see the error. I guess that f should be a length.
• Another unit mismatch at the return values. Sometimes a unit-less value like f or 3.5 is returned, sometimes a length. Guess it should be 3.5 m or even better, write l, not 3.5
• It would look much clearer if you use the programmed "if" statement and not the Excel-like if-function
• You also may consider turning k.s into a function of d.
  
• And here is what I get when I evaluate and plot that function in the range from -2m to 30 m:
  
  Look a bit strange to me. Are you sure that it should look like that? Maybe the expression for d>0.7*L.rule should be, so it would rather look like
  
  
• Last, but not least: It's usually considered rude not to close threads (Re: Can i form a trochoidal wave ?,   how can i get interpolated value without sorting,    interpolations of table) or not to respond to replies at all (Recalling values to table from predefined values,   finding X intercept)!